Question

An object of mass m is moving with a constant velocity v.how much work should be done on the object to bring it to the rest?

Answer 1

Answer:

the object is in motion ,so its energy = kinetic energy = 1/2 mv^2

the kinetic energy of the object ,when it comes to rest = 0

work done on object = change in kinetic energy

= 1/2mv^2 - 0

= 1/2 mv^2

Answer 2

Answer:

$\frac{1}{2} mv^{2}$

Explanation:

Step 1: Given Data:-

Mass of object = m

The initial velocity of the object = v

The final velocity of the object =0

Step 2: Calculating Work Done

We know that,

The work done is equal to the change in the kinetic energy of an object.

Then,

$W = Final \: kinetic \: energy - Initial \: kinetic \: energy$

$W = k.e _{f } - k.e _{i}$

$W = \frac{1}{2}m(0)^{2} - \frac{1}{2} m(v)^{2}$

$W = 0 - \frac{1}{2}mv^{2}$

$W = - \frac{1}{2}mv^{2}$

Hence, $\frac{1}{2}mv^{2}$work should be done on the object in order to bring the object to rest.