A 50 kg boy runs up a flight of stairs 12 m high in 6 seconds. What is his power output?

Let's deconstruct this. Power is energy per second. How much energy is required to lift 50kg by 12m? How much power does it take to impart that energy in 6 seconds?

Two particles, A and B, move with constant velocities and . Initially their position vectors are respectively. The relation between such that two particle, collide with each other