A level mechanics free fall

In reality a stone will not move freely under gravity and will be subject to air resistance.
d) Explain how this would affect the initial speed of the ball.

The answer is that the initial speed would be greater but I don’t understand why. Can someone explain

Reply 1

Bruce Wayne59875

Original post by Aeshakhan

Imagine that you have a stone in freefall but air resistance is negligible. The only force acting on it is its own Weight - which is the only thing that causes it to accelerate downwards until it reaches a new final velocity.

However, let's now include air resistance. What forces are now acting on the stone? You have its weight force and a drag resistive force. Some of that initial kinetic energy is being lost to air resistance. So in order to achieve the same final velocity as before, the initial velocity must've had to have been greater to account for the losses due to the drag.

Hope this makes sense!

(edited 10 months ago)