Question

A 62 kg bike and rider accelerate from 4 m/s to 14 m/s.How much work was done by the rider? Round answerto 4 significant figures.

Answer 1

Given,

The mass of the bike and the rider, m=62 kg

The initial velocity of the bike and the rider, u=4 m/s

The final velocity of the bike and the rider, v=14 m/s

The work done in accelerating an object from its initial velocity to its final velocity is given by the change in its initial and final kinetic energy.

Therefore the work done by the rider is,

`\begin{gathered} W=K_f-K_i \\ =(1)/(2)mv^2-(1)/(2)mu^2 \\ =(1)/(2)m(v^2-u^2) \end{gathered}`

On substituting the known values,

`\begin{gathered} W=(1)/(2)*62*(14^2-4^2) \\ =5580\text{ J} \end{gathered}`

Therefore the work done by the rider is 5580 J