A 6 kg ball falls from height of 32. What willbe potential energy of the ball after 1 second? Use g = 9.8 m/s ^ 2 Calculate answer to one decimal.

A 5 kg ball falls from height of 16 m. What willbe potential energy of the ball after 1 second?  Use g = 9.8 m/s2

A 2-kg brick is thrown downward from a height ?1 = 15 m to ?2 = 10 m. The initial kinetic energy of the brick is ??1 = 25 J. You can use ? = 10 m/s for convenience of calculation.  Assume air resistance is negligible, and nothing heats up or uses fuel during the motion of the brick.1.  If the system of interest is the brick alone, how much work is done by external forces during this motion?

A 56.5-kg hiker starts at an elevation of 1270 m and climbs to the top of a 2660-m peak,  (a) What is  the hiker’s change in potential energy?  (b) What is the minimum work required of the hiker?  (c)  Can the actual work done be greater than this? Explain.