A trolley moves from P to Q along a track. When it reaches Q, its potential energy is $50\ \text{kJ}$ less than it is at P. At P, the trolley has a kinetic energy of $5\ \text{kJ}$. As it travels from P to Q, it does $10\ \text{kJ}$ of work against friction. What is the kinetic energy of the trolley at Q?
- A35 kJ
- B45 kJ
- C55 kJ
- D65 kJ