Answer:
Explanation:
If an object has a higher density than the fluid it is in (fluid can mean liquid or gas), it will sink. If it has a lower density, it will float. Density is determined by an object's mass and volume. If two objects take up the same volume, but have one has more mass, then it also has a higher density.
<span>The amount of kinetic energy an object has
depends on its mass and speed.</span>
If one of two interacting charges is doubled, the force between the charges will double.
Explanation:
The force between two charges is given by Coulomb's law

K=constant= 9 x 10⁹ N m²/C²
q1= charge on first particle
q2= charge on second particle
r= distance between the two charges
Now if the first charge is doubled,
we get 
F'= 2 F
Thus the force gets doubled.
Answer: 7840N
Explanation:
Given that
Potential energy = ?
Mass of sled = 20-kg
Distance = 40 meters
Acceleration due to gravity = 9.8m/s^2
Recall that potential energy is the energy possessed by a body at rest
i.e potential energy = mass m x acceleration due to gravity g x distance h
P.E = mgh
P.E = 20kg x 9.8m/s^2 x 40m
P.E = 7840N
Thus, the potential energy of the sled is 7840N