Answer:
When two players are running full speed at each other on a football field they build up their momentum
Answer:
The poles of an electromagnet can even be reversed by reversing the flow of electricity. If a wire carrying an electric current is formed into a series of loops, the magnetic field can be concentrated within the loops. ... All of their little magnetic fields add together, creating a stronger magnetic field.
Explanation:
Answer:
Explanation:
We have given charge on the particle 
Mass of the charge particle 
From energy of conservation kinetic energy will be equal to potential energy
So at point A

At point a velocity is zero
So 

At point B velocity will be 72 m/sec
So 

So 
Answer:
The magnitude of the electrostatic force decreases by a factor 9
Explanation:
The electrostatic force between two charges is given by:

where
k is the Coulomb's constant
q1 and q2 are the two charges
d is the distance between the two charges
We see that the magnitude of the force is inversely proportional to the square of the distance. If the distance is increased to 3d: d' = 3d, the new electrostatic force would be:

So, the electrostatic force decreases by a factor 9.