(a)[2]
State the type of energy stored in the stretched spring and the type of energy stored in the athlete’s muscles.
(b)[1]
Suggest what occurs if he stretches the spring beyond the limit of proportionality.
(c(i))[2]
During one stretch of the spring, its length changes from $70\,\text{cm}$ to $93\,\text{cm}$. The average force applied by the athlete is $400\,\text{N}$. Calculate the work done by the athlete in one stretch.
(c(ii))[2]
Describe how the athlete can use the value found in (i) to determine his average power over the $60\,\text{s}$.