Question

A 560-g squirrel with a surface area of 930 cm2 falls from a 5.0-m tree to the ground. Estimate its terminal velocity. (Use a drag coefficient for a horizontal skydiver.) What will be the velocity of a 56-kg person hitting the ground, assuming no drag contribution in such a short distance

Answer 1

vf = 9.9 m/s

v_r = 13.9 m/s

Explanation:

Given

m = 560 g

A(t) = 930 cm ² = 0.93 m²

h = 5 m

C = 1

m_2 = 56 Kg / m³

ρ = 1.21 kg

g = 9.8

Terminal Velocity =v_r =?

Final velocity = v_f = ?

Solution:

Surface tension facing the fluid

A_f = A(t)/2 = 0.93/2 = 0.47 m²

Terminal velocity is given by

v_r = √((2 x m x g)/(ρ x C x A_f))

v_r = √(2 x 0.56 x 9.8)/ (1.21 x 1 x 0.47 )

v_r = 13.9 m/s

Now final Velocity

vf² = vi² + 2 x h x g

vi = 0

vf = √(2 x 5 x 9.8)

vf = 9.9