Question

A parachutist, after opening her parachute, finds herself gently floating downward, no longer gaining speed. She feels the upward pull of the harness, while gravity pulls her down. Which of these two forces is greater? Or are they equal in magnitude?

Answer 1

Since parachutist is moving downwards with constant speed

so here we can say

$a = \frac{dv}{dt}$

acceleration is rate of change in velocity

since velocity is given constant here

$a = 0$

So acceleration in this case will be zero

now we know from Newton's II law

$F_{net} = ma$

here a = 0

$F_{net} = 0$

$F_{net} = F_g - F_b$

here

$F_g$= force due to gravity

$F_b$ = force due to buoyancy

So here we can say

$F_g - F_b = 0$

so

$F_g = F_b$

so upward force on it will be balanced by downward force.