Rubbing both pieces cause each piece to have a negative charge.
When two parts have the same they repel each other, so holding one piece up tot he end of the other piece would push it away.
Because one piece is held in the middle by a string, it would rotate the piece in a circle.
If they held the piece to the other end of the one held by a string it would start to rotate in the opposite direction.
Given that the density of heptane is

The mass of heptane is

The density of water is

The mass of water is

The volume of heptane will be

The volume of water will be

Thus, the volume of heptane is 45.32 mL and the volume of water is 37 mL.
The total volume of liquid in the cylinder will be

The total volume of liquid in the cylinder will be 82.32 mL.
Answer:
Elastic potential energy, 
Explanation:
Charge, 
Potential, V = 50 V
It is required to find the electric potential energy in a capacitor stored in it. The formula of the electric potential energy in a capacitor is given by :

So, the electric potential energy stored in the capacitor is 
they are added vectorially. If htere is a resultant force, the thing acclerates. If they vectorially add to zero, thing doesn't move
Answer:
The velocity of the ball before it hits the ground is 381.2 m/s
Explanation:
Given;
time taken to reach the ground, t = 38.9 s
The height of fall is given by;
h = ¹/₂gt²
h = ¹/₂(9.8)(38.9)²
h = 7414.73 m
The velocity of the ball before it hits the ground is given as;
v² = u² + 2gh
where;
u is the initial velocity of the on the root = 0
v is the final velocity of the ball before it hits the ground
v² = 2gh
v = √2gh
v = √(2 x 9.8 x 7414.73 )
v = 381.2 m/s
Therefore, the velocity of the ball before it hits the ground is 381.2 m/s