The stair stepper is a novel exercise machine that attempts to reproduce the work done against gravity by walking up stairs. with each step, brad (of mass 60 kg) simulates stepping up a vertical distance of 0.2 m with this machine. if brad exercises for 13 min per day with a stair stepper at a frequency of 50 steps per minute, what total work he does he do each day? the acceleration of gravity is 9.8 m/s 2 . answer in units of j.

Aballoon is rising vertically upwards at a velocity of 10m/s. when it is at a height of 45m from the ground, a parachute bails out from it. after 3s he opens his parachute and decelerates ata a constant rate 5m/s.when. (a) what was the height of the parachutist above the ground when he opened his parachute? (b)how far is the parachutist from the balloon at t=3s? (c)with what velocity does the parachutist hit the ground? (d)after how long does the parachutist hit the ground after his exist from the balloon?