Calculate the radius of parachute that will slow a 70 Kg person to a terminal velocity of 8 m/s. The person tries to avoid leg injury after touch down by crouching down by 60 cm then calculate the total force at the point of contact?

Answer 1

V_t = SQRT(W/CA)
W= 70KG X 9.81M/S^2 = 687 N (neglecting W of parachute)

V_t = 14/ms ; C = 0.88kg/m^3

A= W/(C x V_t^2) = 687N/(0.88kg/m^3 x 196m^2/s^2)= 3.98 m^2

A= pi x R^2
R= SQRT(A/PI) = 1.3