Answer:
Gravity
Explanation:
When the ball is falling to the ground, there is only one force- gravity. In some cases, there may be air resistance, but that seems to be neglected here.
Normal force:
Cannot be included. Normal force is only applicable when object is on a surface, and it acts perpendicular to the surface. Since the ball is falling, there is no surface, and therefore no normal force. This question gives you unnecessary information, designed to trick you. Please remember when normal force is applicable.
Friction force:
Also only applicable when object is moving, and is on the table. Friction only applies when there is an applied force. There is no applied force when the ball is falling, so therefore no friction force.
Force of fall:
First of all, what is this? There is nothing called force of fall.
Gravity:
This is the only one that applies. Just draw a vector arrow from the bottom of the ball and label it mg (acceleration due to gravity).
Keplers laws states that planets sweep areas in equal times is second
The horizontal displacement of a projectile launched at an angle
Scalar quantity are physical quantities that have just magnitude, not direction.
- It is always positive.
- Examples: Speed, distance
Answer:
7.5 cm
Explanation:
In the figure we can see a sketch of the problem. We know that at the bottom of the U-shaped tube the pressure is equal in both branches. Defining 
Ethyl alcohol density and 
Glycerin density , we can write:
Simplifying:
On the other hand:
Rearranging:
Replacing (2) in (1):
Rearranging:
Data:
