Answer to Question #181000 in Classical Mechanics for naro

Question

If a projectile remains long enough in the air, the horizontal component $Vx$ of its velocity will eventually be (practically) zero and the vertical component $Vy$ will be its terminal velocity $Vt$ in air. Consider a parachutist jumping off a plane which was flying straight and

level at a constant speed, $u$

With the aid of diagram, explain what will happen to its horizontal velocity $Vx$ ,and vertical velocity $Vy$ ,and terminal velocity, $Vt$ before and after the parachutist open its parachute.

Answer 1

As it is mentioned that initially the plane was moving horizontally with the speed u, and when the parachutist jumped off from the plane, then parachutist also will have a horizontal speed u, because as per the newton's first law of motion, there is no external force in the horizontal direction so it's velocity in the horizontal direction will remain unchanged. But in the vertical direction there is a force of gravity is working vertically downwards. So parachutist will experiences a vertical force towards the ground. But here it is given that parachutist obtains a terminal velocity, it means gravitational force get balanced by the thrust force which was gained by the parachutist.