I believe this is what you have to do:
The force between a mass M and a point mass m is represented by

So lets compare it to the original force before it doubles, it would just be the exact formula so lets call that F₁
So F₁ = G(Mm/r^2)
Now the distance has doubled so lets account for this in F₂:
F₂ = G(Mm/(2r)^2)
Now square the 2 that gives you four and we can pull that out in front to give
F₂ =
G(Mm/r^2)
Now we can replace G(Mm/r^2) with F₁ as that is the value of the force before alterations
now we see that:
F₂ =
F₁
So the second force will be 0.25 (1/4) x 1600 or 400 N.
Answer:
it Give only one of them a positive or negative charge
it would be..... C
sorry if I am wrong I tryed to think, At least I try!
Answer:
D. Plate movement
Explanation:
Since they cause earthquakes...
Explanation:
It is given that,
Mass of an object, 
(a) Time period of oscillation, T = 2.4 s
The formula for the time period of spring is given by :

Where
k is the force constant



(b) Displacement in the spring, x = 2.2 m
Energy stored in the spring is given by :



Hence, this is the required solution.