(a)[1]
At first, the road is level and he travels at a steady speed of $3\,\text{m s}^{-1}$. The athlete provides a constant power output of $60\,\text{W}$. Find the resistive force acting on the athlete.
(b)[6]
The athlete then goes up a $150\,\text{m}$ stretch of road that is inclined at $0.8^\circ$ to the horizontal. His speed at the beginning of this stretch is $3\,\text{m s}^{-1}$, and he now exerts a constant driving force of $24\,\text{N}$. Over this section, the total resistive force acting on the athlete has constant magnitude $13\,\text{N}$. Use an energy method to find the athlete's speed at the end of the $150\,\text{m}$ stretch of road.