Question

a skydiver jumps out of a plane. describe how gravitational potential energy changes as the skydiver falls. describe how the skydivers kinetic energy changes when the parachute opens

Answer 1

gravitational potential is directly proportional to the height of the object relative to a reference line and is given as

PE = mgh                        

where m = mass of object , g = acceleration due to                    

gravity   and  h = height of the object above the reference line .

as the skydiver falls , its height above the ground decrease and hence the gravitational potential energy of the skydiver decrease.

as per conservation of energy , total energy of the skydiver must remain constant all the time . hence the decrease in potential energy appears as increase in kinetic energy by same amount to keep the total energy constant

KE + PE = Total energy

so as the skydiver falls , it gains speed and hence the kinetic energy of skydiver increase since kinetic energy is directly proportional to the square of the speed.

when the parachute opens, the skydiver experience force in upward which tries to balance the weight of the skydiver. hence the speed of the skydiver decrease until upward force becomes equal to the downward force. hence the kinetic energy decrease just after the parachute opens