English
Karnataka Board PUCPUC Science Class 11

State if the following statement is true or false. Give a reason for your answer. Work done in the motion of a body over a closed loop is zero for every force in nature. - Physics

Advertisements
Advertisements

Question

State if the following statement is true or false. Give a reason for your answer.

Work done in the motion of a body over a closed loop is zero for every force in nature.

Options

  • True

  • False

MCQ
True or False
Advertisements

Solution

This statement is False.

Explanation:

The work done during the motion of a body over a closed loop is zero exclusively when influenced by a conservative force such as gravity or electrostatic forces. When the forces are non-conservative, like friction, the work done is not zero. Specifically, the work done by friction over a closed loop does not equal zero.

shaalaa.com
  Is there an error in this question or solution?
Chapter 5: Work, Energy and Power - EXERCISES [Page 89]

APPEARS IN

NCERT Physics [English] Class 11
Chapter 5 Work, Energy and Power
EXERCISES | Q 5.7 (c) | Page 89

RELATED QUESTIONS

The gravitational force acting on a particle of 1 g due to a similar particle is equal to 6.67 × 10−17 N. Calculate the separation between the particles.


A monkey is sitting on a tree limb. The limb exerts a normal force of 48 N and a frictional force of 20 N. Find the magnitude of the total force exerted by the limb on the monkey.


Two charged particles placed at a separation of 20 cm exert 20 N of Coulomb force on each other. What will be the force of the separation is increased to 25 cm?


Find the ratio of the magnitude of the electric force to the gravitational force acting between two protons.


The work done by all the forces (external and internal) on a system equals the change in ______.


No work is done by a force on an object if

(a) the force is always perpendicular to its velocity
(b) the force is always perpendicular to its acceleration
(c) the object is stationary but the point of application of the force moves on the object
(d) the object moves in such a way that the point of application of the force remains fixed.


A box is pushed through 4.0 m across a floor offering 100 N resistance. How much work is done by the resisting force?

 

A particle moves from a point \[\overrightarrow{r}_1 = \left( 2 m \right) \overrightarrow{ i } + \left( 3 m \right) \overrightarrow{ j } \] to another point

\[\overrightarrow{r}_2 = \left( 3 m \right) \overrightarrow{ i } + \left( 2 m \right) \overrightarrow{ j } \]  acts on it. Find the work done by the force on the particle during the displacement.


A block of mass m is kept over another block of mass M and the system rests on a horizontal surface (In the following figure). A constant horizontal force F acting on the lower block produces an acceleration \[\frac{F}{2 \left( m + M \right)}\]   in the system, and the two blocks always move together. (a) Find the coefficient of kinetic friction between the bigger block and the horizontal surface. (b) Find the frictional force acting on the smaller block. (c) Find the work done by the force of friction on the smaller block by the bigger block during a displacement d of the system.


A box weighing 2000 N is to be slowly slid through 20 m on a straight track with friction coefficient 0⋅2 with the box. (a) Find the work done by the person pulling the box with a chain at an angle θ with the horizontal. (b) Find the work when the person has chosen a value of θ, which ensures him the minimum magnitude of the force. 


A block of weight 100 N is slowly moved up a smooth incline of inclination 37° by a person. Calculate the work done by the person in moving the block through a distance of 2 m, if the driving force is (a) parallel to the incline and (b) in the horizontal direction.

 

Find the average force needed to accelerate a car weighing 500 kg from rest to 72 km/h through a distance of 25 m.


A block of mass 2 kg kept at rest on an inclined plane of inclination 37° is pulled up the plane by applying a constant force of 20 N parallel to the incline. The force acts for one second.  Show that the work done by the applied force does not exceed 40 J.


A block of mass 2.0 kg is pushed down an inclined plane of inclination 37° with a force of 20 N acting parallel to the incline. It is found that the block moves on the incline with an acceleration of 10 m/s2. If the block started from rest, find the work done (a) by the applied force in the first second, (b) by the weight of the block in the first second and (c) by the frictional force acting on the block in the first second. Take g = 10 m/s2.


Water falling from a 50-m high fall is to be used for generating electric energy. If \[1 \cdot 8 \times {10}^5 \text{ kg } \] of water falls per hour and half the gravitational potential energy can be converted into electrical energy, how many 100 W lamps can be lit with the generated energy?


A uniform chain of length L and mass M overhangs a horizontal table with its two third part on the table. The friction coefficient between the table and the chain is μ . Find the work done by friction during the period the chain slips off the table.

 

A block of mass m is taken from A to B slowly under the action of a constant force R Work done by this force is ______.


What does 'dW' represent in the variable force work calculation?


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×