February/March 2026 Paper 42

A car of mass $1600\mathrm{kg}$ passes through points $A$ and $B$ with speeds $10m/s$ and $12m/s$ respectively. The distance $AB$ is $2\mathrm{km}$. The heights of $A$ and $B$ above sea level are $250\mathrm{m}$ and $200\mathrm{m}$ respectively. The car's engine does no work in moving from $A$ to $B$. There are two forces resisting the motion of the car, a braking force and an additional constant force of magnitude $150\mathrm{N}$. Use an energy method to find the work done by the braking force as the car moves from $A$ to $B$.