Advertisements
Advertisements
Question
Each of the following statement describes a force acting. Which force is causing work to be done?
Options
the weight of a book at rest on a table
the pull of a moving railway engine on its coaches
the tension in an elastic band wrapped around a parcel
the push of a person's feet when standing on the floor
Advertisements
Solution
We will justify all statements one by one as:
(a) The weight of a book at rest on a table cannot do any work as the book is at rest. So, the work done by this force is zero.
(b) The pulling force applied by the railway engine on its coaches is doing work, as the force applied by the engine results in the motion of the coaches.
(c) The tension force in an elastic band wrapped around a parcel cannot do any work, as there is no motion of the parcel because of the tension force of the rubber band.
(d) The push of a person’s feet on a floor when he is standing cannot do any work because there is no motion involved due to the applied force.
Therefore, the answer is -
(b) The pull of a moving railway engine on its coaches.
APPEARS IN
RELATED QUESTIONS
In case of negative work, the angle between the force and displacement is :
Give two examples of couple actions in our daily life.
Does the earth move around the sun with a uniform velocity?
Is work done a scalar or a vector physical quantity?
Give two examples of work done.
Write an expression for work done by a force depends?
In the following case write yes, if the work is being done and no if no work is being done.
A boy climbing up a staircase.
State the amount of work done by an object when it moves in a circular path for one complete rotation. Give a reason to justify your answer.
A force can cause an object to change its ______.
Look at the activity below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
An engine is pulling a train.
