Energy, work and power — practice question

A train with mass $240\,000\,\text{kg}$ is moving up a slope that makes an angle of $4^\circ$ to the horizontal. A constant resistive force of magnitude $18\,000\,\text{N}$ acts on the train. At the moment when its speed is $15\,\text{m s}^{-1}$, the train’s deceleration is $0.2\,\text{m s}^{-2}$.