Question

A body of mass 5 kg, initially at rest, is subjected to a force of 20 N. What is the kinetic energy acquired by the body at the end of 10 s?

Answer 1

Mass m = 5 kg, Force F = 20 N, time t = 10 s

F = ma => 20 = 5a => a = 4 m/s^2.

v = u + at

v = 0 + 4*10

v=40m/s

Kinetic Energy KE = (1/2)mv^2 = (1/2)(5)(1600) = 4000 J.