5. A 50 kg skydiver jumps from a height of 20 m. What would be his kinetic and potential energies when he is halfway down? Assume g=10m/s.
6. A man of mass 60 kg climbs up 50 steps of a stair in 2 minutes. If each step is 20 cm high, calculate the power used in climbing the stairs. Given g=10m/s^2.