I'm not sure about the magnitude, but the direction of the normal force is upward.
Answer:The speed if hailstone dependly largely on its size. A hailstone with a diameter of 0.39 inches,falls wit a speed of 20mph while a hailstone with 3.1 inches in diameter falls at a speed of 110mph.
No speed does not depend on the distance that the hailstone falls.
Explanation: There are other factors that affect the speed of the falling hailstone apart from its size.They are:
1. Friction between the air and the hailstone
2. Wind condition( windy or moist air)
3. The rate at which it melts falling.
Answer:
The speed of Susan is 2.37 m/s
Explanation:
To visualize better this problem, we need to draw a free body diagram.
the work is defined as:

here we have the work done by Paul and the friction force, so:


Now the change of energy is:

The car will gain new momentum if it's velocity is doubled or tripled.