One common application of conservation of energy in mechanics is to determine the speed of an object. although the simulation doesn’t give the skater's speed, you can calculate it because the skater's kinetic energy is known at any location on the track. consider again the case where the skater starts 7 m above the ground and skates down the track. what is the skater's speed when the skater is at the bottom of the track?

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?