1.) What type of energy is associated with motion? Kinetic energy
2)List 3 items that store chemical energy ?
Coal
Apple
Chemical batteries
A front is defined as a "boundary" that separates two masses of different air densities. I am not entirely sure, but I think the answers are either C or D, but I'm mostly convinced it's option D.
The question is missing, however, I guess the problem is asking for the value of the force acting between the two balls.
The Coulomb force between the two balls is:

where

is the Coulomb's constant,

is the intensity of the two charges, and

is the distance between them.
Substituting these numbers into the equation, we get

The force is repulsive, because the charges have same sign and so they repel each other.
What is it asking? It is sort of blurry
Answer:

Explanation:
As we know that backpack is kicked on the rough floor with speed "v"
So here as per force equation in vertical direction we know that

so normal force on the block is given as

now the magnitude of kinetic friction on the block is given as


now when bag is sliding on the floor then net deceleration of the block due to friction is given as


now we know that bag hits the opposite wall at L distance away in time t
so we have


