Two spheres have a gravitational force between them of 45 N. If the distance between the masses
is increased to 4.0 times its original distance, what
is the new force?

The new force is 2.8125 N

Explanation:

Newton’s Law of Universal Gravitation

Objects attract each other with a force that is proportional to their masses and inversely proportional to the square of the distance.  

Where:

m1 = mass of object 1

m2 = mass of object 2

r     = distance between the objects' center of masses

G   = gravitational constant: 6.67\cdot 10^{-11}~Nw*m^2/Kg^2

Suppose two spheres have a gravitational force between them of F = 45 N. Now increase the distance to r'=4r. The new force F' is:

Substituting the original value of the force:

F' = 2.8125 N

The new force is 2.8125 N

answer: the metamorphic rocks are formed when they are exposed to high pressure and high temperatures. this happens when one of the earth's plates comes in contact with the other plate by traveling in opposite directions, straight into each other or slipping under one another. the friction that is caused by this activity results in   melting of rocks and when it cools they are known as metamorphic rocks. this process needs a controlled amount of pressure and temperature otherwise it may turn into magma.

a skateboard rolling across the street - apex