Question

An engine performs 6400 j of work on a motorbike the motorbike and the rider have a combined mass of 200 kg if the bike started at rest what is the speed of the bike after the work is performed

Answer 1

The work done by the engine is converted into kinetic energy of the motorbike+rider system:

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

where

W=6400 J is the work

m=200 kg is the mass of the system

v is the speed acquired by the motorbike

Rearranging the equation and substituting the numbers in, we find

$v=\sqrt{\frac{2W}{m}} =\sqrt{\frac{2(6400 J)}{200 kg}} =8 m/s$