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# Selina solutions for Concise Physics Class 6 ICSE chapter 4 - Simple Machines [Latest edition]

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#### Chapters ## Chapter 4: Simple Machines

### Selina solutions for Concise Physics Class 6 ICSE Chapter 4 Simple Machines Objective questions

Objective questions | Q 1.1

State whether the following statement is True or False.

A boy does work while pushing a wall.

• True

• False

Objective questions | Q 1.2

State whether the following statement is True or False.

A machine performs work by itself.

• True

• False

Objective questions | Q 1.3

State whether the following statement is True or False.

In an ideal machine, work done on load is equal to the work done by effort.

• True

• False

Objective questions | Q 1.4

State whether the following statement is True or False.

All levers are force multipliers.

• True

• False

Objective questions | Q 1.5

State whether the following statement is True or False.

A pulley changes the direction of force.

• True

• False

Objective questions | Q 1.6

State whether the following statement is True or False.

An inclined plane always has the mechanical advantage of more than 1.

• True

• False

Objective questions | Q 2.1

Fill in the blank:

The useful work done by an actual machine is always ............ than the work done on the machine.

Objective questions | Q 2.2

Fill in the blank:

In class II levers, the load is in between fulcrum and .........

Objective questions | Q 2.3

Fill in the blank:

The mechanical advantage of class .............. lever is always less than 1.

Objective questions | Q 2.4

Fill in the blank:

A pulley is used to change ........................

Objective questions | Q 2.5

Fill in the blank:

Mechanical advantage of an inclined plane is always .................

Objective questions | Q 3

Match the following:

 Column A Column B (a) Needle (1) class II lever (b) Doorknob (2) inclined plane (c) Ramp (3) Class I lever (d) Lemon crusher (4) Wheel and axle (e) Seesaw (5) wedge
Objective questions | Q 4.1

Select the correct alternative:

For an ideal machine, the efficiency is

• greater than unity

• less than unity

• equal to unity

• depends on the value of load

Objective questions | Q 4.2

Select the correct alternative:

Mechanical advantage of a machine is defined as:

Objective questions | Q 4.3

Select the correct alternative:

The mechanical advantage of a lever is equal to:

• Load arm / Effort arm

• Effort arm / Load arm

• Load arm + Effort arm

• Load arm — Effort arm

Objective questions | Q 4.4

Select the correct alternative:

A pulley is used because of it

• has the mechanical advantage greater than one

• has 100% efficiency

• helps to apply the force in a convenient direction

• requires more effort to raise a less load.

Objective questions | Q 4.5

Select the correct alternative:

Wheel is used with axle because

• sliding friction is less than the roffing friction

• rolling friction is less than the sliding friction

• they work as the inclined plane

• They help us to change the direction of force.

### Selina solutions for Concise Physics Class 6 ICSE Chapter 4 Simple Machines Short/Long answer questions

Short/Long answer questions | Q 1

When is work said to be done by a force?

Short/Long answer questions | Q 2

What is energy?

Short/Long answer questions | Q 3

What do you understand by a machine?

Short/Long answer questions | Q 4

What is the principle on which a machine works?

Short/Long answer questions | Q 5

State two functions of a machine.

Short/Long answer questions | Q 6

Name six simple machines. Give an example of each machine.

Short/Long answer questions | Q 7

Define the term ‘work input’ and ‘work output’ in relation to a machine.

Short/Long answer questions | Q 8

Explain the term mechanical advantage of a machine.

Short/Long answer questions | Q 9

Define the term efficiency of a machine.

Short/Long answer questions | Q 10

What is an ideal machine?

Short/Long answer questions | Q 11

Can a machine have an efficiency of 100%? Give a reason to support your answer.

Short/Long answer questions | Q 12

A machine is 75% efficient’. What do you understand by this statement?

Short/Long answer questions | Q 13

What is a lever?

Short/Long answer questions | Q 14

Describe three orders of levers giving an example of each. Draw neat diagrams showing the positions of fulcrum, load, and effort in each kind of lever.

Short/Long answer questions | Q 15

What do you mean by the mechanical advantage of a lever?

Short/Long answer questions | Q 16

Which class of lever has the mechanical advantage always more than 1? Give an example.

Short/Long answer questions | Q 17

Which class of lever has the mechanical advantage always less than 1? Give an example.

Short/Long answer questions | Q 18.1

Give one example of a class I lever in a case where the mechanical advantage is more than 1?

Short/Long answer questions | Q 18.2

Give one example of a class I lever in a case where the mechanical advantage is equal to 1?

Short/Long answer questions | Q 18.3

Give one example of a class I lever in a case where the mechanical advantage is less than 1?

Short/Long answer questions | Q 19.01

Name the class to which the following lever belong:

A pair of scissors

Short/Long answer questions | Q 19.02

Name the class to which the following lever belong:

a lemon squeezer

Short/Long answer questions | Q 19.03

Name the class to which the following lever belong:

a nutcracker

Short/Long answer questions | Q 19.04

Name the class to which the following lever belong:

a pair of sugar tongs

Short/Long answer questions | Q 19.05

Name the class to which the following lever belong:

a beam balance

Short/Long answer questions | Q 19.06

Name the class to which the following lever belong:

an oar rowing a boat.

Short/Long answer questions | Q 19.07

Name the class to which the following lever belong:

a wheelbarrow

Short/Long answer questions | Q 19.08

Name the class to which the following lever belong:

a see-saw

Short/Long answer questions | Q 19.09

Name the class to which the following levers belong:

a pair of pliers

Short/Long answer questions | Q 19.1

Name the class to which the following lever belong:

a crowbar

Short/Long answer questions | Q 20

The diagram given below shows the three kinds of levers. Name the class of each lever and give one example of each class.

(a) (b) (c) Short/Long answer questions | Q 21.1

Draw diagram to illustrate the position of fulcrum, load, and effort, of the following:

a see-saw.

Short/Long answer questions | Q 21.2

Draw diagram to illustrate the position of fulcrum, load, and effort, of the following:

a beam balance

Short/Long answer questions | Q 21.3

Draw diagram to illustrate the position of fulcrum, load, and effort, of the following:

a nutcracker

Short/Long answer questions | Q 21.4

Draw diagram to illustrate the position of fulcrum, load, and effort, of the following:

a pair of forceps

Short/Long answer questions | Q 22

How can you increase the mechanical advantage of a lever?

Short/Long answer questions | Q 23

How does the friction at the fulcrum affect the mechanical advantage of the lever?

Short/Long answer questions | Q 24

State three differences between the three classes of levers.

Short/Long answer questions | Q 25

What is a pulley?

Short/Long answer questions | Q 26

What is the mechanical advantage of an ideal pulley?

Short/Long answer questions | Q 27

The mechanical advantage of an actual pulley is less than one. Give a reason. What is the justification for using the pulley then?

Short/Long answer questions | Q 28

Draw a neat labelled diagram showing a pulley being used to lift a load. How are load and effort related in an ideal situation?

Short/Long answer questions | Q 29.2

What is the use of an inclined plane? Give two examples where it is used.

Short/Long answer questions | Q 30

What is a screw? Give two examples.

Short/Long answer questions | Q 31

What are the wheel and axle? Give two examples.

Short/Long answer questions | Q 32

How does a wheel help in moving the axle?

Short/Long answer questions | Q 33

What is a wedge? Give two examples.

Short/Long answer questions | Q 34.1

Name the machine to which the following belong:

Beam balance

Short/Long answer questions | Q 34.2

Name the machine to which the following belong:

Lemon crusher

Short/Long answer questions | Q 34.3

Name the machine to which the following belong:

Sugar tongs

Short/Long answer questions | Q 34.4

Name the machine to which the following belong:

Ramp

Short/Long answer questions | Q 34.5

Name the machine to which the following belong:

Doorknob

Short/Long answer questions | Q 34.6

Name the machine to which the following belong:

Needle

Short/Long answer questions | Q 35

What care would you take to increase the life span of a machine which you use?

Short/Long answer questions | Q 36

Select the correct statement :
(a) A wheel barrow is a lever of class I.
(b) The efficiency of a machine is always 100%
(c) Friction in moving parts of a machine reduces its efficiency.
(d) No lever has the mechanical advantage greater than 1.
(e) It is easier to lift a load vertically up than to push it along an inclined plane.
(f) A screw is made by two inclined planes placed together.

### Selina solutions for Concise Physics Class 6 ICSE Chapter 4 Simple Machines Numericals

Numericals | Q 1

In a machine, an effort of 10 kgf is applied to lift a load of 100 kgf. What is its mechanical advantage?

Numericals | Q 2

The mechanical advantage of a machine is 5. How much load it can exert for the effort of 2 kgf?

Numericals | Q 3

The mechanical advantage of a machine is 2. It is used to raise a load of 15 kgf. What effort is needed?

Numericals | Q 4

A lever of length 100 cm has the effort of 15 kgf at a distance of 40 cm from the fulcrum at one end. What load can be applied at its other end?

Numericals | Q 5

In a lever, the fulcrum is at one end at a distance of 30 cm from the load and effort is at the other end at a distance of 90 cm from the load. Find :
(a) the length of load arm,
(b) the length of effort arm, and
(c) the mechanical advantage of the lever.

### Selina solutions for Concise Physics Class 6 ICSE Chapter 4 Simple Machines Additional questions

What is a machine?

What do you understand by a complex machine?

Name the simplest of all types of machines.

State the principle of levers.

What is a Class I lever?

### Selina solutions for Concise Physics Class 6 ICSE Chapter 4 Simple Machines Exercises

Exercises | Q 1

The force applied on a machine to do work is called the

• effort

• efficiency

• fulcrum

Exercises | Q 2

If the effort lies between the fulcrum and the load, then the lever belongs to which class?

• Class I

• Class II

• Class III

• Class IV

Exercises | Q 3

Which of the following is a Class II lever?

• Pliers

• A beam balance

• A nut-cracker

• A knife

Exercises | Q 4

A pair of scissors is an example of a/an

• wedge

• lever

• inclined plane

• screw

Exercises | Q 5

The mechanical advantage of an inclined plane is always

• greater than 1

• less than 1

• equal to 1

• zero

Exercises | Q 6

The effort required to lift a load of 800 N by using a lever having a mechanical advantage of 1.6 is

• 1080 N

• 240 N

• 720 N

• 500 N

Exercises | Q 7

A machine made up of two or more sloping surface is known as a

• wedge

• screw

• pulley

• lever

### Selina solutions for Concise Physics Class 6 ICSE Chapter 4 Simple Machines Exercises

Exercises | Q 1

State if the following statement is true or false. Correct the statement if it is false.

There are four types of simple machines.

• True

• False

Exercises | Q 2

State if the following statement is true or false. Correct the statement if it is false.

The load and effort can act at a single point in a lever.

• True

• False

Exercises | Q 3

State if the following statement is true or false. Correct the statement if it is false.

A screw is a special case of an inclined plane.

• True

• False

Exercises | Q 4

State if the following statement is true or false. Correct the statement if it is false.

The effort required to insert a screw into wood is less than that needed to insert a nail into wood.

• True

• False

Exercises | Q 5

State if the following statement is true or false. Correct the statement if it is false.

A single movable pulley is a pulley that has its axis of rotation fixed.

• True

• False

Exercises | Q 6

State if the following statement is true or false. Correct the statement if it is false.

A rotation spindle tap is an example of a wheel-and-axle arrangement.

• True

• False

Exercises | Q 7

State if the following statement is true or false. Correct the statement if it is false.

A sewing needle is a wedge type simple machine.

• True

• False

Exercises | Q 8

State if the following statement is true or false. Correct the statement if it is false.

Work done by a machine is always more than the work done on a machine.

• True

• False

### Selina solutions for Concise Physics Class 6 ICSE Chapter 4 Simple Machines Exercises

Exercises | Q 1

Answer the following in a word or two or in a sentence.

Given an example of a Class I lever.

Exercises | Q 2

Answer the following in a word or two or in a sentence.

Which type of machine is used to squeeze a lemon?

Exercises | Q 3

Answer the following in a word or two or in a sentence.

Exercises | Q 4

Answer the following in a word or two or in a sentence.

Name the type of machine made by putting two inclined planes together.

Exercises | Q 5

Answer the following in a word or two or in a sentence.

Give one example of a machine used to multiply speed.

Exercises | Q 6

Answer the following in a word or two or in a sentence.

Write the formula for calculating the efficiency of a machine.

### Selina solutions for Concise Physics Class 6 ICSE Chapter 4 Simple Machines Exercises

Exercises | Q 1

Explain the various functions that a machine can perform.

Exercises | Q 2

What is the basis of the classification of levers?

Exercises | Q 3

What is the function of a screw? Give anyone the use of a screw.

Exercises | Q 4

Using a suitable example, describe how a machine acts as a force multiplier.

Exercises | Q 5

What do you understand by the term efficiency of a machine’?

Exercises | Q 6

Mention any two methods by which we can take care of machines.

### Selina solutions for Concise Physics Class 6 ICSE Chapter 4 Simple Machines Exercises

Exercises | Q 1

Draw simplified diagrams by clearly showing the position of load, effort, and fulcrum for Class I, Class II, and Class III levers.

Exercises | Q 2.1

How does a pulley make work simpler?

Exercises | Q 2.2

Differentiate between a single fixed pulley and a single movable pulley.

Exercises | Q 3

What is a wedge? Explain the principle on which it works by giving suitable examples.

Exercises | Q 4.1

What is an inclined plane?

Exercises | Q 4.2

What is the use of an inclined plane? Give two examples where it is used.

### Selina solutions for Concise Physics Class 6 ICSE Chapter 4 Simple Machines Exercises

Exercises | Q 1

Give a reason for the following.

Machines are able to make our work convenient.

Exercises | Q 2

Give a reason for the following.

The efficiency of a machine is always less than 100%.

Exercises | Q 3

Give a reason for the following.

The front end of a boat is shaped like a wedge.

### Selina solutions for Concise Physics Class 6 ICSE Chapter 4 Simple Machines Exercises

Exercises | Q 1

Solve the following numerical problem.

The length of a lever is 2 m. Calculate its mechanical advantage if the fulcrum is situated at a distance of 40 cm from the effort.

Exercises | Q 2

Solve the following numerical problem.

The length of the load arm of a lever is 6 m long and the effort arm is 3 m long. What is the effort required to lift a load of 40 N?

Exercises | Q 3

Solve the following numerical problem.

Calculate the mechanical advantage of a crowbar of length 240 cm if its fulcrum is situated at a distance of 40 cm from the load.

Exercises | Q 4

Solve the following numerical problem.

What effort will be required to lift a load of 500 N by a single movable pulley? [Hint: Mechanical advantage of a single movable pulley is two].

## Chapter 4: Simple Machines ## Selina solutions for Concise Physics Class 6 ICSE chapter 4 - Simple Machines

Selina solutions for Concise Physics Class 6 ICSE chapter 4 (Simple Machines) 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 Concise Physics Class 6 ICSE solutions in a manner that help students grasp basic concepts better and faster.

Further, we at Shaalaa.com provide such solutions so that students can prepare for written exams. Selina textbook solutions can be a core help for self-study and acts as a perfect self-help guidance for students.

Concepts covered in Concise Physics Class 6 ICSE chapter 4 Simple Machines are Concept of Energy, Simple Machines - Basic Concept, Simple Machines - Mechanical Advantage, Types of Simple Machines - Lever, Types of Simple Machines - Wheel and Axle, Types of Simple Machines - Pulley, Types of Simple Machines - Inclined Plane, Types of Simple Machines - Wedge, Types of Simple Machines - Screw, Different Orders of Levers, Numerical Based on Mechanical Advantage Or Leverage - Load × Load Arm = Effort × Effort Arm..

Using Selina Class 6 solutions Simple Machines exercise by students are an easy way to prepare for the exams, as they involve solutions arranged chapter-wise also page wise. The questions involved in Selina Solutions are important questions that can be asked in the final exam. Maximum students of CISCE Class 6 prefer Selina Textbook Solutions to score more in exam.

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