Answer: William Thomson, better known as Lord Kelvin
They use x-rays to diagnose broken bones
Explanation:
a) Balloon is being thrown down and is speeding up;
mg >
b) Balloon is in the air on its way down and moving with constant speed.
=mg
c) The Balloon is on the ground and rest instantaneously
mg = Normal
d) Balloon is moving slowly downward;
e) Because, at the peak of trajectory drag force is 0.
Drag force = 0
The net force will be zero. Since the forces are in opposite direction and equal amount, they will cancel out.