# Frank solutions for ICSE Class 10 Physics Part 2 chapter 1 - Force, Work, Energy and Power [Latest edition]

#### Chapters ## Chapter 1: Force, Work, Energy and Power

Exercise 1.1Exercise 1.2Exercise 1.3Exercise 1.4Exercise 1.5Exercise
Exercise 1.1 [Page 13]

### Frank solutions for ICSE Class 10 Physics Part 2 Chapter 1 Force, Work, Energy and Power Exercise 1.1 [Page 13]

Exercise 1.1 | Q 1 | Page 13

Define moment of force and state its SI unit.

Exercise 1.1 | Q 2 | Page 13

Its moment of a force scalar or a vector quantity?

Exercise 1.1 | Q 3 | Page 13

Name the physical quantity whose SI unit is Nm.

Exercise 1.1 | Q 4 | Page 13

What is meant by a translational motion? Give one example.

Exercise 1.1 | Q 5 | Page 13

What is meant by a rotatory motion? Give one example.

Exercise 1.1 | Q 6 | Page 13

What is the relationship between Nm and dyne cm?

Exercise 1.1 | Q 7 | Page 13

State the factors on which moment of force about a point depends.

Exercise 1.1 | Q 8 | Page 13

What do you understand by the clockwise and anti clockwise moment of force?

Exercise 1.1 | Q 9 | Page 13

State the condition when a force produces
(i) linear motion.
(ii) rotational motion, in a body.

Exercise 1.1 | Q 10 | Page 13

Why is easier to open a door by applying the force at its free end?

Exercise 1.1 | Q 11 | Page 13

Why does a spanner have a long handle?

Exercise 1.1 | Q 12 | Page 13

What do you mean by equilibrium of a body?

Exercise 1.1 | Q 13 | Page 13

State the condition when a body is in (i) static, (ii) dynamic, equilibrium. Give one example each of static and dynamic equilibrium.

Exercise 1.1 | Q 14 | Page 13

State two conditions for a body acted upon by several forces to be in equilibrium.

Exercise 1.1 | Q 15 | Page 13

State the principle of moments.

Exercise 1.1 | Q 16 | Page 13

Draw a neat labeled diagram to show the direction of two forces acting on a body to produce rotation in it. Also mark the point about which rotation takes place.

Exercise 1.1 | Q 17 | Page 13

Give two examples of couple action in our daily life.

Exercise 1.1 | Q 18 | Page 13

P, Q and R are three forces which act as shown in fig. The point O lies in the same plane. Given, P = Q = R = 10N

(i) Which force has the least moment about O? Give a reason.

(ii)Which force has the greatest moment about O? Give a reason.

Exercise 1.1 [Page 14]

### Frank solutions for ICSE Class 10 Physics Part 2 Chapter 1 Force, Work, Energy and Power Exercise 1.1 [Page 14]

Exercise 1.1 | Q 1 | Page 14

What do you understand by the term couple? State its effect.

Exercise 1.1 | Q 2 | Page 14

Define moment of couple. Write its S.I. unit. Prove that
Moment of couple= Force x Couple arm.

Exercise 1.1 | Q 3 | Page 14

A body is provided at a point. A force of 20 N is applied at a distance of 40 cm from the pivot. Find the moment of force about the pivot.

Exercise 1.1 | Q 4 | Page 14

The moment of a force 10 N about a point 0 is 4 Nm. Calculate the distance of point of application of force from the point 0.

Exercise 1.1 | Q 5 | Page 14

A mechanic can open a nut by applying a force of 200 N while using a lever handle of 50 cm length. How long handle is required if he wants to open it by applying a force of only 50 N?

Exercise 1.1 | Q 6 | Page 14

State the conditions of equilibrium for a rigid body.

Exercise 1.2 [Page 17]

### Frank solutions for ICSE Class 10 Physics Part 2 Chapter 1 Force, Work, Energy and Power Exercise 1.2 [Page 17]

Exercise 1.2 | Q 1 | Page 17

What do you mean by uniform circular motion?

Exercise 1.2 | Q 2 | Page 17

A uniform circular motion is an accelerated motion. Justify it.

Exercise 1.2 | Q 3 | Page 17

What is a centripetal force?

Exercise 1.2 | Q 4 | Page 17
Name the SI unit of centripetal force.
Exercise 1.2 | Q 5 | Page 17

Is centrifugal force considered as the force of reaction of the centripetal force?

Exercise 1.2 | Q 6 | Page 17

Explain the difference between a uniform linear motion and a uniform circular motion.

Exercise 1.2 | Q 7 | Page 17

Name the force needed for circular motion. What is the direction of the force?

Exercise 1.2 | Q 8 | Page 17

Which of the following quantity remains constant in a uniform circular motion?

•  force

• speed

• velocity

• acceleration

Exercise 1.2 | Q 9 | Page 17

Is the motion of moon around the earth in circular path an accelerated motion?

Exercise 1.2 | Q 10 | Page 17

Does the earth move around the sun with a uniform velocity?

Exercise 1.2 | Q 11 | Page 17

What do you mean by a centrifugal force?

Exercise 1.2 | Q 12 | Page 17

Name the force acting away from the centre of circular path.

Exercise 1.3, Exercise 1.2 [Page 28]

### Frank solutions for ICSE Class 10 Physics Part 2 Chapter 1 Force, Work, Energy and Power Exercise 1.3, Exercise 1.2 [Page 28]

Exercise 1.3 | Q 1 | Page 28

What is the use of a fixed pulley?

Exercise 1.3 | Q 2 | Page 28

What is an ideal machine?

Exercise 1.3 | Q 3 | Page 28

Write the relation between mechanical advantage, velocity ratio and efficiency.

Exercise 1.2 | Q 4 | Page 28

Can a machine be 100% efficient?

Exercise 1.3 | Q 5 | Page 28

Define velocity ratio? State its unit.

Exercise 1.3 | Q 6 | Page 28

What is the purpose of a machine?

Exercise 1.3 | Q 7.1 | Page 28

Give an example for each of the following uses of a machine:

to obtain gain in force,

Exercise 1.3 | Q 7.2 | Page 28

Give an example for each of the following uses of a machine:

to change the point of application of force

Exercise 1.3 | Q 7.3 | Page 28

Give an example of the following uses of a machine:

to change the direction of force

Exercise 1.3 | Q 7.4 | Page 28

Give an example of the following uses of a machine:

to obtain gain in speed

Exercise 1.3 | Q 8 | Page 28

The diagram below shows a pulley arrangement. (i) In the diagram, mark the direction of the forces due to tension, acting on the pulley P.

(ii) What is the purpose of the pulley Q?

(iii) If the tension is T newton, deduce the relation between T and E.

(iv) Calculate the velocity ratio of the arrangement.

(v) Assuming that the efficiency of the system is 100%, what is the mechanical advantage?

(vi) Calculate the value of E

Exercise 1.3 | Q 9 | Page 28

What is a block and tackle system of pulleys?

Exercise 1.3 | Q 10 | Page 28
In which direction will the force be applied when a single pulley is used with a mechanical advantage greater than unity?
Exercise 1.3 | Q 11 | Page 28
In a single fixed pulley, If the effort moves by a distance y downwards, by what height is the load raised?
Exercise 1.3 | Q 12 | Page 28

What is a single movable pulley? What is its mechanical advantage in the ideal case?

Exercise 1.3 | Q 13 | Page 28

Name the type of single pulley that can act as a force multiplier. Draw a labeled diagram of the pulley mentioned by you.

Exercise 1.3 | Q 14.1 | Page 28

Give reason for the following:
In a single fixed pulley, the velocity ratio is always more than the mechanical advantage.

Exercise 1.3 | Q 14.2 | Page 28

Give reason for the following:

The efficiency of a pulley is always less than 100%

Exercise 1.3 | Q 14.3 | Page 28

Give reason for the following:

In case of a block and tackle arrangement, the mechanical advantage increases with the increase in the number of pulleys.

Exercise 1.3 [Page 29]

### Frank solutions for ICSE Class 10 Physics Part 2 Chapter 1 Force, Work, Energy and Power Exercise 1.3 [Page 29]

Exercise 1.3 | Q 1.1 | Page 29

Name a machine which is used to:

multiply force

Exercise 1.3 | Q 1.2 | Page 29

Name a machine which is used to:

multiply speed

Exercise 1.3 | Q 1.3 | Page 29

Name a machine which is used to:

change the direction of force applied.

Exercise 1.3 | Q 2 | Page 29

Write two uses of pulleys. Is pulley a force multiplier?

Exercise 1.3 | Q 3 | Page 29

In the fig draw a tackle to lit a load by applying the torce in a convinient direction. Mark the position of load and effort. (i) If the load is raised by 1 m, Through what distance will the effort move?

(ii) State how many strands of tackle are supporting the load?

(iii) What is the mechanical advantage of the sysytem?

Exercise 1.3 | Q 4 | Page 29

Fig shown a block and tackles system of pulleys used to lift a load. (i) How many strands of tackle are supporting the load?

(ii) Draw arrows to represent tension in each stand.

(iii) What is the mechanical advantage of the system?

(iv) When load is pulled up by a distance 1 m how far does the effort end move?

Exercise 1.3 | Q 5 | Page 29

What is a block and tackle system of pulleys?

Exercise 1.3 | Q 6 | Page 29

Fig show a system of four pulleys. The upper two pulleys are fixed and the lower two are movable. (i) Draw a string around the pulleys. Also show the place and direction in which the effort is applied.

(ii) What is the velocity ratio of the system?

(iii) What is the mechanical advantage of the system?

(iv) What assumption do you make in arriving at your answer in part (iii)?

Exercise 1.4 [Page 37]

### Frank solutions for ICSE Class 10 Physics Part 2 Chapter 1 Force, Work, Energy and Power Exercise 1.4 [Page 37]

Exercise 1.4 | Q 1 | Page 37

Work is the application of a ....... through a distance.

Exercise 1.4 | Q 2 | Page 37

A boy does work when he pushes against a brick wall. (yes/no).

Exercise 1.4 | Q 3 | Page 37

What is the SI unit of work?

Exercise 1.4 | Q 4 | Page 37

Nm is the unit of .......

Exercise 1.4 | Q 5 | Page 37

One joule is the amount of work done when a force of ......... moves a body through a distance of .......

Exercise 1.4 | Q 6 | Page 37

What is the work done when no net force is applied on the body?

Exercise 1.4 [Page 38]

### Frank solutions for ICSE Class 10 Physics Part 2 Chapter 1 Force, Work, Energy and Power Exercise 1.4 [Page 38]

Exercise 1.4 | Q 1 | Page 38

What is the work done when the object acted upon by a force remains at rest?

Exercise 1.4 | Q 2 | Page 38

What is the work done when the force on the object and the displacement of the object are perpendicular to each other?

Exercise 1.4 | Q 3 | Page 38

Is work done a scalar or a vector physical quantity?

Exercise 1.4 | Q 4 | Page 38

Work is a scalar quantity because it is a measure of transfer of energy without indicating any direction

Exercise 1.4 | Q 5 | Page 38
What is the work done by the gravitational force of the earth on a satellite revolving around the earth?
Exercise 1.4 | Q 6 | Page 38
What is the work when a load of 500 kg is lifted vertically by 5 m? Given, g = 10 ms-2. Express your answer in kilo joule.
Exercise 1.4 | Q 7 | Page 38

A man lifts a mass of 10 kg from the floor to a shelf 4 meter high. If g = 10 ms-2, what is the work done?

Exercise 1.4 | Q 8 | Page 38

What is the work done against gravity when a body is moved horizontally along a frictionless surface?

Exercise 1.4 | Q 9 | Page 38
What do you mean by the term 'work'?
Exercise 1.4 | Q 10 | Page 38
What are the quantities on which the work done depends?
Exercise 1.4 | Q 11 | Page 38

When you move upstairs, do you perform some work?

Exercise 1.4 | Q 12 | Page 38
What should be the angle between the directions of the displacement and the applied force so that the work done is zero?
Exercise 1.4 | Q 13 | Page 38
Why is the work done on an object moving along a circular path zero?
Exercise 1.4 | Q 14 | Page 38

In which one of the following cases is the work done more?  When the angle between the direction of motion and that of the force is (i) 90°     (ii) 0°.

Exercise 1.4 | Q 15 | Page 38

A man carrying a suitcase in his hand is walking horizontally. What is the work done against gravity?

Exercise 1.4 | Q 16 | Page 38
What is the work done on a body by the gravitational force towards the centre of the path acting when it moves along a circular path?
Exercise 1.4 | Q 17 | Page 38
What is the work done on the earth by the gravitational force of the sun during its motion around the sun?
Exercise 1.4 | Q 18 | Page 38

What do you mean by a kilo joule?

Exercise 1.4 | Q 19 | Page 38

How many joules are there in 1 mega joule?

Exercise 1.4 | Q 20 | Page 38

Define 'joule'.

Exercise 1.4 | Q 21 | Page 38

What is the ratio of SI units to CGS units of 'work'?

Exercise 1.4 | Q 22 | Page 38

An engine does 54,000 J of work by exerting a force of 6000 N on it. What is the displacement in the direction of the force?

Exercise 1.4 | Q 23 | Page 38

How much force is applied on a body when 150 J of work is done in displacing the body through a distance of 10 m in the direction of the force?

Exercise 1.4 | Q 24 | Page 38

Work done by a force is equal to the product of ....... and ....

Exercise 1.4 | Q 25 | Page 38

Give two examples of work done.

Exercise 1.4 | Q 26 | Page 38

On what factors does the work done by a force depend?

Exercise 1.4 | Q 27 | Page 38

Write an expression for work done by a force depends?

Exercise 1.4 | Q 28 | Page 38

Write an expression for the work done against gravity.

Exercise 1.4 | Q 29 | Page 38

No work is done by a man moving on a horizontal road while carrying a box on his head. Explain.

Exercise 1.4 | Q 30 | Page 38

Is power a scalar quantity?

Exercise 1.4 | Q 31 | Page 38

Can every force produce work?

Exercise 1.4 | Q 32 | Page 38

Distinguish between work and power.

Exercise 1.4 | Q 33.1 | Page 38

Complete the following sentences:
The SI unit of work is ....... and of power is .......

Exercise 1.4 | Q 33.2 | Page 38

Complete the following sentences:

Kilowatt is the unit of ....... and kWh is the unit of

Exercise 1.4 | Q 33.3 | Page 38

Complete the following sentences:
Joule is the unit of .......

Exercise 1.4 | Q 33.4 | Page 38

Complete the following sentences:

1 J = ........ Erg.

Exercise 1.4 | Q 33.5 | Page 38

Complete the following sentences:

1 H.P. = ........ W.

Exercise 1.4 | Q 34 | Page 38

A weight lifted a load of 200 kgf to a height of 2.5 m in 5 s. calculate: (i) the work done, and (ii) the power developed by him. Take g= 10 N kg-1.

Exercise 1.4 [Page 39]

### Frank solutions for ICSE Class 10 Physics Part 2 Chapter 1 Force, Work, Energy and Power Exercise 1.4 [Page 39]

Exercise 1.4 | Q 1 | Page 39

A boy of mass m climbs up a staircase of vertical height h. What is the work done by the boy against the force of gravity? What would have been the work done if he uses a lift in climbing the same vertical height?

Exercise 1.4 | Q 2 | Page 39

Can work done be zero even if force acts on the body?

Exercise 1.4 | Q 3 | Page 39
What is the relation between 1 H.P. and 1 kW?
Exercise 1.4 | Q 4 | Page 39
It takes 20 s for A to climb up the stairs, while B does the same in 15 s. compare the (i) work done, and (ii) power developed by A and B.
Exercise 1.4 | Q 5 | Page 39
State and define the SI unit of power.
Exercise 1.4 | Q 6 | Page 39
Write the SI and CGS units of power. How are they related?
Exercise 1.4 | Q 7 | Page 39

A machine raises a load of 750 N through a height of 16 m in 5s. calculate:
(i)    work done by machine,
(ii)    power at which the machine works.

Exercise 1.4 | Q 8 | Page 39

Name the physical quantity whose MKS units are kgm2s-3.

Exercise 1.5 [Page 53]

### Frank solutions for ICSE Class 10 Physics Part 2 Chapter 1 Force, Work, Energy and Power Exercise 1.5 [Page 53]

Exercise 1.5 | Q 1 | Page 53
Define kinetic energy.
Exercise 1.5 | Q 2 | Page 53
Give two examples of kinetic energy.
Exercise 1.5 | Q 3 | Page 53
Write the SI units of energy.
Exercise 1.5 | Q 4 | Page 53
Name the physical quantity which is equal to the energy of a body.
Exercise 1.5 | Q 5 | Page 53
Name the physical quantity which is associated with the work done by a body.
Exercise 1.5 | Q 6 | Page 53
Is kinetic energy a scalar or a vector physical quantity?
Exercise 1.5 | Q 7 | Page 53
If the speed of a body is doubled, what happens to its kinetic energy?
Exercise 1.5 | Q 8 | Page 53
What are the physical parameters on which the kinetic energy of a body depends?
Exercise 1.5 | Q 9 | Page 53
Can a body possess zero kinetic energy?
Exercise 1.5 | Q 10 | Page 53
Name the type of energy possessed by a moving bullet.
Exercise 1.5 | Q 11 | Page 53
A body of mass 2 kg is moving with a speed of 20 ms-1. What is its K.E.?
Exercise 1.5 | Q 12 | Page 53
A moving object of mass 30 kg has 60 J of kinetic energy. What is its speed?
Exercise 1.5 | Q 13 | Page 53
What type of energy is possessed by a flowing water?
Exercise 1.5 | Q 14 | Page 53
If the speed of a particle is increased four times, how will its kinetic energy be affected?
Exercise 1.5 | Q 15 | Page 53
A bus and a car have the same K.E. which of the two should be moving faster? Explain.
Exercise 1.5 | Q 16 | Page 53
A body is thrown vertically upwards. Its velocity keeps on changing. What happens to its K.E. when does its velocity become zero?
Exercise 1.5 | Q 17 | Page 53
What change should be effected in the velocity of a body to maintain the same K.E., if its mass is increased four times?
Exercise 1.5 | Q 18 | Page 53
The K.E. of a body is 5 J. What will be its K.E. when its speed is doubled?
Exercise 1.5 | Q 19 | Page 53
Name the parameters that can change the K.E.
Exercise 1.5 | Q 20 | Page 53
Give an example of a body possessing no K.E.
Exercise 1.5 | Q 21 | Page 53
Define potential energy.
Exercise 1.5 | Q 22 | Page 53
What are the factors on which P.E. of a body depends?
Exercise 1.5 | Q 23 | Page 53
What is the amount of energy spent in lifting 1 kg through 1 m? Take g = 10 ms-2.
Exercise 1.5 | Q 24 | Page 53
Give two examples of P.E.
Exercise 1.5 | Q 25 | Page 53
What is the P.E. of a body lying on the surface of the earth?
Exercise 1.5 | Q 26 | Page 53
What is the amount of energy spent by the heart in pumping blood through the body?
Exercise 1.5 | Q 27 | Page 53
Name the type of energy possessed by a body due to a change in configuration.
Exercise 1.5 | Q 28 | Page 53
How is energy stored in a clock?
Exercise 1.5 | Q 29 | Page 53
What is the P.E. of a body of mass M at a height H above the earth's surface?
Exercise 1.5 | Q 30 | Page 53
Is P.E. a vector or a scalar quantity?
Exercise 1.5 | Q 31 | Page 53

Name the type of energy possessed by a
(i) stretched catapult        (ii) hot iron
(iii) wound up clock

Exercise 1.5 | Q 32 | Page 53

An object is dropped from a height H. when is its
(i)    P.E. maximum,
(ii)    K.E. maximum,
(iii)    P.E. = K.E.?

Exercise 1.5 | Q 33 | Page 53

A cricket ball is thrown up from the earth's surface. What happens to its P.E.
(a)    during the motion
(b)    at the highest point?

Exercise 1.5 [Page 54]

### Frank solutions for ICSE Class 10 Physics Part 2 Chapter 1 Force, Work, Energy and Power Exercise 1.5 [Page 54]

Exercise 1.5 | Q 1 | Page 54
What is the difference between K.E. and P.E.?
Exercise 1.5 | Q 2 | Page 54
What is meant by the transformation of energy?
Exercise 1.5 | Q 3 | Page 54
Does the total energy of a body always remain constant?
Exercise 1.5 | Q 4 | Page 54
Is energy a scalar or a vector physical quantity?
Exercise 1.5 | Q 5 | Page 54
Can we destroy every energy associated with a body?
Exercise 1.5 | Q 6 | Page 54
Define energy of a body.
Exercise 1.5 | Q 7 | Page 54
State the law of conservation of energy.
Exercise 1.5 | Q 8 | Page 54
A dry cell converts one form of energy into another. Name the two forms.
Exercise 1.5 | Q 9 | Page 54
Name the device that converts electrical energy into mechanical energy.
Exercise 1.5 | Q 10 | Page 54
Name the device that converts mechanical energy into electrical energy.
Exercise 1.5 | Q 11 | Page 54
Name four different forms of energy.
Exercise 1.5 | Q 12 | Page 54
What kind of energy transformation takes place at a thermal power station?
Exercise 1.5 | Q 13.1 | Page 54

Name the energy changes for the following:
electric ball

Exercise 1.5 | Q 13.2 | Page 54

Name the energy changes for the following:
bicycle brakes

Exercise 1.5 | Q 13.3 | Page 54

Name the energy changes for the following:
pendulum

Exercise 1.5 | Q 13.4 | Page 54

Name the energy changes for the following
human body

Exercise 1.5 | Q 13.5 | Page 54

Name the energy changes for each of the following cases:
dynamo

Exercise 1.5 | Q 14 | Page 54
What is meant by power?
Exercise 1.5 | Q 15 | Page 54
Write the SI units of power.
Exercise 1.5 | Q 16 | Page 54
Define one horse power.
Exercise 1.5 | Q 17 | Page 54
Define the unit 'watt'. How is it related to horse power?
Exercise 1.5 | Q 18 | Page 54

A body does 20 J of work in 10 s. What is its power?

Exercise 1.5 | Q 19 | Page 54

Name the physical quantity associated with the 'rate of doing work'.

Exercise 1.5 | Q 20 | Page 54

An electric motor drives a machine which lifts a mass of 4 kg through a height of 10 m in 5 s at a constant speed. Assuming g = 10 ms-2, calculate

(i) the amount of work done,    (ii) the power of the machine.

Exercise 1.5 | Q 21 | Page 54
Name the practical unit of power.
Exercise 1.5 | Q 22 | Page 54
In what form is energy stored in a wrist watch?
Exercise 1.5 | Q 23 | Page 54
A log of wood cut by a saw becomes hot. From where does this heat energy come?
Exercise 1.5 | Q 24 | Page 54
Our hands become warm when we rub them against each other. Why?
Exercise 1.5 | Q 25 | Page 54
The head of a nail becomes warm when it is hammered into a plank of wood. Explain the series of energy transformation taking place in the process.
Exercise 1.5 | Q 26 | Page 54

A 100 W electric lamp emits energy in the form of light at the rate 10 J per second. What percentage of electric energy does the lamp transform into light energy?

Exercise 1.5 | Q 27 | Page 54
A horse exerts a pull on a cart of 300 N so that the horse-cart system moves with a uniform speed 18 km/h on a level road. Calculate the power developed by the horse in watt and also find its equivalent in horse power.
Exercise 1.5 | Q 28 | Page 54

If an electric bulb of 100 watt is lighted for 2 hours, how much electric energy would be consumed?

Exercise 1.5 | Q 29 | Page 54

A woman pulls a bucket of water of total mass 5 kg from a well which is 10 s. calculate the power used by her.

Exercise [Page 56]

### Frank solutions for ICSE Class 10 Physics Part 2 Chapter 1 Force, Work, Energy and Power Exercise [Page 56]

Exercise | Q 1 | Page 56
What do you mean by the turning effect of a force?
Exercise | Q 2 | Page 56
Name the physical quantity whose SI unit is Nm.
Exercise | Q 3 | Page 56
What is meant by a torque?
Exercise | Q 4 | Page 56
A body is pivoted at a point. A force of 10 N is applied at a distance of 30 cm from the pivot. Find the moment of force about the pivot.
Exercise | Q 5 | Page 56
Is moment of a force a scalar quantity?
Exercise | Q 6 | Page 56
Is it easier to turn a steering wheel of large diameter than that of small diameter? Why?
Exercise | Q 7 | Page 56
Define the centre of gravity of a body.
Exercise | Q 8 | Page 56
What is meant by equilibrium?
Exercise | Q 9 | Page 56
What is meant by the principle of moments?
Exercise | Q 10 | Page 56
What is the difference between mass and weight?
Exercise | Q 11 | Page 56
The moment of a force of 20 N about a fixed point 0 is 10 Nm. Calculate the distance of the point 0 from the line of action of the force.
Exercise | Q 12 | Page 56
What is meant by the term 'center of gravity of a body'?
Exercise | Q 13 | Page 56
Where is the centre of gravity of a uniform ring situated?
Exercise | Q 14 | Page 56
State the factors on which the centre of gravity of a body depends.
Exercise | Q 15 | Page 56
Can the centre of gravity be situated outside the material of the body? Give an example.
Exercise | Q 16.1 | Page 56

Following Fig shows piece of cardboard of uniform thickness cut into different shapes. Draw two lines to indicate the position of centre of gravity G. Exercise | Q 16.2 | Page 56

Following Fig shows piece of cardboard of uniform thickness cut into different shapes. Draw two lines to indicate the position of centre of gravity G. Exercise | Q 16.3 | Page 56

Following Fig shows piece of cardboard of uniform thickness cut into different shapes. Draw two lines to indicate the position of centre of gravity G. Exercise | Q 16.4 | Page 56

Following Fig shows piece of cardboard of uniform thickness cut into different shapes. Draw two lines to indicate the position of centre of gravity G. Exercise | Q 16.5 | Page 56

Following Fig shows piece of cardboard of uniform thickness cut into different shapes. Draw two lines to indicate the position of centre of gravity G. Exercise [Page 57]

### Frank solutions for ICSE Class 10 Physics Part 2 Chapter 1 Force, Work, Energy and Power Exercise [Page 57]

Exercise | Q 1 | Page 57
What is meant by a centripetal force? Is it same as centrifugal force?
Exercise | Q 2 | Page 57
Name the physical quantity whose unit is kgfm. Define it.
Exercise | Q 3 | Page 57
What is meant by the turning effect of force? Give two examples.
Exercise | Q 4 | Page 57
What is meant by the state of equilibrium of a body?
Exercise | Q 5 | Page 57
What is the difference between static and dynamic equilibrium?
Exercise | Q 6 | Page 57
State the conditions of a stable equilibrium of a body.
Exercise | Q 7 | Page 57

A body is acted upon by two forces, each of magnitude F, but in opposite directions. State the effect of the forces when
(a) Both forces act at the same point of the body.
(b) The two forces act at two different points of the body at a separation d.

Exercise | Q 8 | Page 57

A wheel of diameter 3 m is shown in fig. 2 with axle at 0. A force F = 8 N is applied at Q in the direction shown in figure. Calculate the moment of force about:
(i)    centre o, and
(ii)    point p. Exercise | Q 9 | Page 57

Calculate the resultant moment of forces about O and state its direction in fig. Exercise | Q 10 | Page 57

State the principle of moments. A meter scale is pivoted at 30 cm mark and it is in equilibrium when a mass of 40 g is suspended from 10 cm mark. Calculate the mass of the ruler.

Exercise | Q 11 | Page 57

State the principle of moments. A meter scale is pivoted at 30 cm mark and it is in equilibrium when a mass of 40 g is suspended from 10 cm mark. Calculate the mass of the ruler. Exercise | Q 12 | Page 57

Fig. 5 shows a uniform meter scale weighing 200 gf. Provided at its centre. Two weights 300 gf and 500 gf are suspended from the ruler as shown in the diagram. Calculate the resultant torque of the ruler and hence calculate the distance from mid-point where a 100 gf should be suspended to balance the meter scale. Exercise | Q 13 | Page 57

A meter scale is pivoted at its mid point and a 50 g mass suspended from the 20 cm mark. What mass balances the ruler when suspended from 65 cm mark?

Exercise | Q 14 | Page 57

What do you mean by the state of equilibrium? What are the conditions for stable equilibrium?

Exercise [Page 58]

### Frank solutions for ICSE Class 10 Physics Part 2 Chapter 1 Force, Work, Energy and Power Exercise [Page 58]

Exercise | Q 1 | Page 58

Fig. shows the dimensions of an acute angled triangle. By geometrical construction mark the C.G. of the triangle. Exercise | Q 2 | Page 58

A right-angled triangle cardboard piece is placed as shown in fig. 7. Redraw the diagram showing the relative position of the vertices of the triangle when it is suspended by a pin from the hole A. Explain why the position changes? Exercise | Q 3.1 | Page 58

Give scientific reason for the following:
It is easier to push a boy standing on one leg than on both legs.

Exercise | Q 3.2 | Page 58

Give scientific reason for the following:

When a man climbs a slope he bends forward.

Exercise | Q 3.3 | Page 58

Give scientific reason for the following:

There are chances of toppling when a truck takes a sharp turn   especially when it is not fully loaded

Exercise | Q 3.4 | Page 58

Give scientific reason for the following:

A man runs in the direction of train while getting down from a moving train.

Exercise | Q 3.5 | Page 58

Give scientific reason for the following:

Passengers in a bus are pushed backward when it starts suddenly.

Exercise | Q 4 | Page 58
What are the different methods by which you can increase the stability of a body?
Exercise | Q 5 | Page 58

(i) What do you understand by the term couple of forces?
(ii) Calculate the moment of a couple shown in fig. Exercise | Q 6.1 | Page 58

Even though the Tower of Pisa is leaning through an angle it does not fall.

Exercise | Q 6.2 | Page 58

Give scientific reason for the following:
While climbing a hill you will try to bend your body forward.

Exercise | Q 6.3 | Page 58

Give scientific reason for the following:
In a moving bus the standing passenger stands keeping both his legs apart.

Exercise | Q 6.4 | Page 58

Give scientific reason for the following:

In a doubled decker bus passengers are not allowed to stand in the upper deck.

Exercise | Q 7 | Page 58

Three forces A, B and C are acting on a rigid body which can turn about O in fig.9. If all the three forces are applied simultaneously, in which direction will the body move? Explain. Exercise | Q 8 | Page 58

Fig.  shows a uniform meter scale weighing 100 N pivoted at its centre. Two weights of 500 N and 300 N are hung from the ruler as shown in fig. (i)    Calculate total clockwise and anticlockwise moments.
(ii)    Calculate difference in clockwise moment and anticlockwise moment.
(iii)    Calculate the distance from O where a 100 N weight should be suspended to balance the meter scale.

Exercise | Q 9 | Page 58

A meter scale is provided at 10 cm mark and is balanced by suspending 400 g from 0 cm mark (fig. ). Calculate the mass of meter scale. Exercise [Page 59]

### Frank solutions for ICSE Class 10 Physics Part 2 Chapter 1 Force, Work, Energy and Power Exercise [Page 59]

Exercise | Q 1 | Page 59

Define the term work. Name the CGS and SI unit of work.

Exercise | Q 2 | Page 59

The following are some of the energy transformations.
A. Electrical to light
B. Work to heat
C. Chemical to light
D. Electrical to sound
E. Mechanical to electrical
Identify the energy transformation that takes place in the following by inserting the corresponding letter in the shape provided.
(i)    A candle flame
(ii)    A torch is lighted
(iii)    A microphone is used in a meeting
(iv)    A cycle dynamo
(v)    A piece of metal is being filed

Exercise | Q 3 | Page 59

A boy pulls a box up to 10 m with a force of 5 kgf. Calculate the work done by him.

Exercise | Q 4 | Page 59

Calculate the amount of work done by a child carrying a bag of 20 kg when he moves a distance of 40 m in
(a) Vertical direction, and
(b) Horizontal direction

Exercise | Q 5 | Page 59

(a) Define power and name its unit.
(b) A girl weighting 50 kg climbs up 60 steps each of 20 cm height in 5 minutes. Calculate the power developed.

Exercise | Q 6 | Page 59
Define energy and name its unit.
Exercise | Q 7 | Page 59

When an elevator starts to move down suddenly we experience 'weightlessness'. Explain.

Exercise | Q 8 | Page 59

A block of mass 20 kg is pulled up a slope (fig.12) with a constant speed by applying a force of 500 N parallel to the slope. A and B are initial and final positions of the block.
(a)    Calculate the work done by the force in moving the block from A and B.
(b)    Calculate the potential energy gained by the block. Exercise | Q 9 | Page 59

How fast should a boy weighting 30 kg run so that his kinetic energy is 375 joule?

Exercise | Q 10 | Page 59

A girl of mass 50 kg runs up a flight of 40 steps in 20 seconds. If each step in 20 cm high, calculate the power developed by the girl. (g= 10 ms-2).

Exercise | Q 11 | Page 59
A water pump raises 80 kg of water through a height of 20 m in 10 s. Calculate the power of the pump.
Exercise | Q 12 | Page 59
The truck has to apply a force of 3000 N to overcome friction while moving with a uniform speed of 36 kmhr-1. What is the power developed by the truck?
Exercise | Q 13 | Page 59

Define energy and state the unit of energy and the law of conservation of energy.

Exercise | Q 14 | Page 59

List any six forms of energy and write a short note on each of them.

Exercise | Q 15 | Page 59

What do you understand by 'potential energy' and 'Kinetic energy'? Give three examples of each to illustrate your answer.

Exercise | Q 16 | Page 59

A bullet is of mass 'm' g and is moving with a velocity 'v' m/s. Find the kinetic energy of the bullet when
(a) The mass is doubled,
(b) The velocity is tripled.

Exercise | Q 17 | Page 59
A block of iron of mass 400 kg is used as a pile driver. If it is raised to a height of 20 meters, calculate the potential energy possessed by the iron block. (Assume g= 10 ms-2).
Exercise | Q 18 | Page 59

Identify the type of energy possessed by the body in each of the following:
(a) A coiled spring of the toy car
(b) A hammer which is raised
(c) A stone shot from a catapult
(d) Water stored in the overhead tank
(e) A tadpole moving in water.

Exercise [Page 60]

### Frank solutions for ICSE Class 10 Physics Part 2 Chapter 1 Force, Work, Energy and Power Exercise [Page 60]

Exercise | Q 1.1 | Page 60

Fill in the boxe to show the corresponding energy transformation. Exercise | Q 1.2 | Page 60

Fill in the boxe to show the corresponding energy transformation. Exercise | Q 1.3 | Page 60

Fill in the boxe to show the corresponding energy transformation. Exercise | Q 1.4 | Page 60

Fill in the boxe to show the corresponding energy transformation. Exercise | Q 1.5 | Page 60

Fill in the boxe to show the corresponding energy transformation. Exercise | Q 2.1 | Page 60

State the energy changes which take place when Water stored in the dam is used to turn turbine in dynamo.

Exercise | Q 2.2 | Page 60

State the energy changes which take place when An electric bulb glows when it is connected to a source of electric current.

Exercise | Q 2.3 | Page 60

State the energy changes which take place when A piece of magnesium wire is burnt in a jar of oxygen.

Exercise | Q 2.4 | Page 60

State the energy changes which take place when A stone dropped from the top of a cliff reaches the ground after some time.

Exercise | Q 2.5 | Page 60

State the energy changes which take place when A toy car with a wound spring moves on ground.

Exercise | Q 3.1 | Page 60

Give an example
Electrical energy changes of sound energy.

Exercise | Q 3.2 | Page 60

Give an example
Chemical energy changes to heat energy.

Exercise | Q 3.3 | Page 60

Give an example

Chemical energy changes to electrical energy.

Exercise | Q 3.4 | Page 60

Give an example

Light energy changes to electrical energy.

Exercise | Q 3.5 | Page 60

Give an example

Electrical energy changes to heat energy.

Exercise | Q 4 | Page 60
Find the kinetic energy of a car of mass 1000 kg traveling at 72 km/h.
Exercise | Q 5 | Page 60
A bullet of mass 25 g has a velocity of 600 ms-1. What is the kinetic energy of the bullet? If it penetrates 50 cm into a target, find the resistive force offered by the target.
Exercise | Q 6 | Page 60
A lead bullet moving at 70 ms-1 is brought to rest on hitting a target. If 80% of its energy is converted into heat energy, find the rise in temperature (Sp. Heat cap. Of lead is 140 J/kgK).
Exercise | Q 7 | Page 60
If 60% of the potential energy available in a waterfall is converted into heat energy, find the height of the waterfall, when the temperature difference between the top and the bottom of the fall is 0.210C (sp. Heat cap. Of water = 4200J/kgK).
Exercise | Q 8.1 | Page 60

Define Simple machine

Exercise | Q 8.2 | Page 60

Define Lever

Exercise | Q 8.3 | Page 60

Exercise | Q 8.4 | Page 60

Define Velocity Ratio

Exercise | Q 8.5 | Page 60

Define Efficiency

Exercise | Q 9 | Page 60

Class I lever can have M.A. = 1, M.A. < 1 and M.A. > 1. Explain each giving examples.

Exercise [Page 61]

### Frank solutions for ICSE Class 10 Physics Part 2 Chapter 1 Force, Work, Energy and Power Exercise [Page 61]

Exercise | Q 1 | Page 61

Fig. shows a spade. It is being used to lift soil weighing 30N from the ground. (a)    Mark the direction of the least force on the handle necessary to keep the spade balanced.
(b)    Calculate the least force on the handle necessary to keep the spade balanced (the weight of the spade is negligible).
(c)    If the left hand was move towards the soil on the spade, would the force on the handle necessary to keep the soil balance the greater or less? Give a reason for your answer.
(d)    To which class of lever does the spade belong?

Exercise | Q 2 | Page 61
A crowbar 4 m long has its fulcrum 50 cm from one end. What minimum effort is required to displace a weight of 500 kgf? Calculate the M.A. of the crowbar.
Exercise | Q 3 | Page 61

A pair of nut crackers is 12 cm long. An effort of 10 gf is required to crack a nut which is passed at a point 3 cm from the finger. Calculate the load Fig. Exercise | Q 4 | Page 61

(a)  Fig represents an incomplete diagram of a simple string pulley      system. Copy this diagram on a new page and complete it and mark where the effort must be applied to lift the load.
(b) What is the velocity ratio of this system?
(c) If the pulley system is 80% efficient and the load is 720 N, then
(i) What effort must be applied to lift the load?
(ii) What work must be done must be done in lifting the load through   a distance of 2 m using this machine? Exercise | Q 5.1 | Page 61

What makes a balance faulty?

Exercise | Q 5.2 | Page 61

A faulty balance of equal arms but pans of unequal weight is used to find the weight of a body. By the method of double weighing the weights are found as 8 kg and 8.2 kg. Find the actual weight of the body.

Exercise | Q 5.3 | Page 61

The arms of a beam balance are 20 cm and 21 cm, but the pans are of equal weight. By the method of double weighing the weights are found to be 1000 g and 20 g. Find the actual weight of the body

Exercise | Q 5.4 | Page 61

A faulty balance of unequal arms and pans of unequal weights is used to find the true weight of a metal. By double weighing the weights are found to be 1210 g and 1000 g. Calculate the true weight of the metal.

## Chapter 1: Force, Work, Energy and Power

Exercise 1.1Exercise 1.2Exercise 1.3Exercise 1.4Exercise 1.5Exercise ## Frank solutions for ICSE Class 10 Physics Part 2 chapter 1 - Force, Work, Energy and Power

Frank solutions for ICSE Class 10 Physics Part 2 chapter 1 (Force, Work, Energy and Power) include all questions with solution and detail explanation. This will clear students doubts about any question and improve application skills while preparing for board exams. The detailed, step-by-step solutions will help you understand the concepts better and clear your confusions, if any. Shaalaa.com has the CISCE ICSE Class 10 Physics Part 2 solutions in a manner that help students grasp basic concepts better and faster.

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Concepts covered in ICSE Class 10 Physics Part 2 chapter 1 Force, Work, Energy and Power are Introduction of Work, Measurement of Work, Concept of Power, Concept of Energy, Mechanical Energy and Its Different Forms, Types of Mechanical Energy: Potential Energy, Types of Potential Energy, Gravitational Potential Energy, Definition of Work, Work Done by the Force of Gravity (W = mgh), Different Forms of Energy, Theoretical verification of K + U = Constant for a freely falling body, Types of Mechanical Energy: Kinetic Energy, Types of Kinetic Energy, Conversion of Potential Energy into Kinetic Energy, Transformation of Energy, Application of Principle of Conservation of Energy to a Simple Pendulum, Principle of Conservation of Energy, Machines, Simple Machines, Machines (Numerical), Lever, Pulley, Technical Terms Related to a Machine, Principle of Machine, Relationship between efficiency (ղ), mechanical advantage (M.A.) and velocity ratio (VR), Classes of Lever, Single Fixed Pulley, Single Movable Pulley, Combination of Pulleys, Force, Translational and Rotational Motions, Turning Effect of a Force, Equilibrium of Bodies and Its Types, Centre of Gravity, Moment of Force Or Torque, Couple, Principle of Moments, Uniform Circular Motion, Centripetal Acceleration and Centripetal Force, Centrifugal Forces.

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