A body of mass 5 kg initially at rest, is subjected to a force of 20N. What is the kinetic energy acquired by the body at the end of half minute?

Explanation

Here, mass of the body, `m =5 kg`
initial velocity of the body, `u = 0`
force acting on the body, `F =20 N`
time for which the force acts, `t =10 s`
If a is the acceleration produced in the body.
`a =(F)/(m) =(20N)/(5kg) = 4 m//s^2`
Let `upsilon` be the velocity of the body after `10 s`.
Clearly, `upsilon = u + at = 0 +(4m//s^2)(10 s) = 40 m//s`
Kinetic energy acquired by the body,
`E_k =(1)/(2)mupsilon^2 =(1)/(2)(5kg)(40m//s)^2 = 4000 J`