CBSE Class 9 Science Question 16 of 33

Work and Energy — Question 16

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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

The kinetic energy of an object of mass m, moving with a velocity, v, is given by the expression,

Kinetic energy = 12\dfrac{1}{2}mv2

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

An external force has to absorb energy from the object, i.e., do negative work on it, equal to its kinetic energy = 12-\dfrac{1}{2}mv2