Question

A box of mass m = 2 kg is kicked on a rough horizontal plane with an initial velocity v_0 . If the net work done on the crate during its entire motion , until it comes to rest , is -36 J , then the initial velocity v_0 of the box is equal to :

Answer 1

Given:

The mass of the box is m = 2 kg

The work done is W = -36 J

The final velocity of the object is

`v_f=\text{ 0 m/s}`

To find the initial velocity of the box.

Step-by-step explanation:

The initial velocity of the box can be calculated as

`\begin{gathered} Work\text{ done = change in kinetic energy} \\ W=(1)/(2)m(v_f^2-v_o^2) \\ -36=(1)/(2)*2(0^2-v_o^2) \\ -v_(_0)^2=-36 \\ v_o=6\text{ m/s} \end{gathered}`

Hence, the initial velocity of the box is 6 m/s.