Question

A 1200 kg car initally traveling at 20 m/s increases its speed to 28m/s. how much work did the cars engine have to do to cause this change

Answer 1

Given :

A 1200 kg car initially traveling at 20 m/s increases its speed to 28m/s.

To Find :

How much work did the cars engine have to do to cause this change.

Solution :

We know, work done is given by :

Work Done = Final Kinetic Energy - Initial Kinetic Energy

`Work \ Done = (mv_f^2)/(2) - (mv_i^2)/(2)\\\\Work \ Done = (1200 * 28^2)/(2) - (1200* 20^2)/(2)\\\\Work \ Done = 230400\ J\\\\Work \ Done = 230.4 \ kJ`

Therefore, work done by car engine is 230.4 kJ.