5 22 pts Air density p 12 kgm3 Calculate the terminal veloci

5. (22 pts) Air density p 1.2 kg/m3. Calculate the terminal velocities of Professor Xu in both cases: a) Falling with a parachute (Diameter D 11 m, total mass m 70 kgy, b) Falling with an umbrella (Diameter D 1.2 m, total mass m Gikgi. ParAdyule,A Umbrella Ca-13 1.3 CD, 1.3

Solution

Drag force = Cd rho* V*V A/2

at equilibrium, drag force = weight at terminal velocity

for first case, get V = sqrt( 2*70*9.81*4/( 1.3*1.2*pi*121) = 3.04 m/s

second case, V = 28.8 m/sec with mass 60 *9.81 N