Question

Find the air resistance acting on a parachuter that jumps from a plane. The mass of the parachuter is 85 kg, the coefficient of shape is 0.88 kg/m^3, and the velocity is 25 m/s. The area facing the direction of the motion is 0.30m^2.

Compare the magnitudes of the air resistance and the weight of the parachuter. What is the magnitude and direction of the net force?

Answer 1

Mass of the parachute, m = 85 kg

Coefficient of shape, ρCd = 0.88 kg/m3

Velocity, v =25 m/s

Area facing the direction of motion, A = 0.30 m2

Air resistance force on the parachute, F = ρCd A v2/2= 0.88 x 0.3 x 25 x 25/2= 82.5 N

Air resistance force on the parachute, F = 82.5 N

Weight of the parachute, W = mg = 85 x 9.81 = 833.85 N

Weight of the parachute/ air resistance = W/F = 833.85/82.5 = 10.11

Net force, Fnet = W – F = 833.85 – 82.5 =751.35 N

The net force on the parachute acts vertically downwards.