Question

16. An object of mass, m is moving with a constant velocity, v. How much work should

be done on the object in order to bring the object to rest?

​

Answer 1

Explanation:

An object with mass 'm' moving with velocity 'V' has kinetic energy of

2

1

mv

2

.

In order to bring it to rest, its velocity has to be reduced to zero, and in order to

accomplish that, the kinetic energy has to be drained off and sent somewhere else.

An external force has to absorb energy from the object, i.e. do negative work on it,

equal to its kinetic energy,or

−

2

1

mv

2

.

Answer 2

Ans. In order to bring the object to rest the work done must be equal to the kinetic energy of

the moving object

17. Calculate the work required to be done to stop a car of 1500 kg moving at a velocity