Physics

Problem

A gardener pushes a lawn roller of mass

80\,\text{kg}

that is initially at rest on level ground. a. (i) He does

320\,\text{J}

of work on the roller. Calculate the speed attained. b. (ii) Immediately after this, he continues to supply power at a constant rate of

160\,\text{W}

for

5\,\text{s}

. Assuming all the power goes into increasing the kinetic energy of the roller, determine its speed at the end of the

5\,\text{s}

interval.