DRAG FORCE PHYSICS!!?

A)

At the terminal velocity the downward force of gravity balances the upward drag force, so the net force on the raindrop is 0 and it falls at constant speed.

So Fd = -m*g = -4*10^-5kg * 9.8 m/s^2 = -3.92*10^-4 N

Also Fd = -b*v when v = 5 m/s

so b = -Fd / v = 3.92*10^-4 / 5 = 7.84*10^-5 N.s/m <= ANS

B)

The force of gravity is reduced by the drag force, so the free-fall acceleration from rest will be

a = g - Fd/m instead of g.

v = 63% of 5m/s = 3.15 m/s

v = a*t = (g - Fd/m)*t = 3.15 m/s

At v=3.15 m/s Fd = -b*v = 2.47*10^-4 N

so Fd/m = 6.17 m/s^2 (= reduction in acceleration)

Hence t = v / a = 3.15 / (9.8 - 6.17) s = 0.87 s <= ANS

The arrow keys ought to administration course - that's the organic and organic inclination. Use J for leaping, F to increasw stress, shift F or ctrl-F to cut back it, A for acceleration, V for velocity (assuming which you at the instant are not portraying rather physics - indoors the rather international, increasing stress creates acceleration that will boost velocity).

All physics is drag force physics...it's a drag, do the math and figure out and what force, lol