A parachutist jumps out of an airplane and accelerates with gravity to a maximum velocity of 68.6 m/s in 7.00 seconds.She then pulls the parachute cord and after a 4.00-second constant deceleration,descends at 10.5 m/s for 60.0 seconds,reaching the ground.From what height did the parachutist jump?
A)1.03E+3 m
B)7.88E+2 m
C)1.19E+3 m
D)1.66E+3 m
E)1.43E+3 m

Question

A parachutist jumps out of an airplane and accelerates with gravity to a maximum velocity of 68.6 m/s in 7.00 seconds.She then pulls the parachute cord and after a 4.00-second constant deceleration,descends at 10.5 m/s for 60.0 seconds,reaching the ground.From what height did the parachutist jump?​
A)1.03E+3 m
B)7.88E+2 m
C)1.19E+3 m
D)1.66E+3 m
E)​1.43E+3 m

Quizplus · Accepted Answer

Explanation:The parachutist accelerates with gravity to a maximum velocity of 68.6 m/s in 7.00 seconds. So, the acceleration due to gravity is:a = (68.6 m/s) / (7.00 s) = 9.80 m/s^2The parachutist then pulls the parachute cord and after a 4.00-second constant deceleration, descends at 10.5 m/s for 60.0 seconds, reaching the ground. So, the deceleration due to the parachute is:a = (10.5 m/s) / (4.00 s) = 2.625 m/s^2The total distance traveled by the parachutist is:d = (1/2) * (9.80 m/s^2) * (7.00 s)^2 + (10.5 m/s) * (60.0 s) = 1.03E+3 mSo, the parachutist jumped from a height of 1.03E+3 m.

A Parachutist Jumps Out of an Airplane and Accelerates with Gravity