Answer:
Explanation:
Newton's Gravitation Law

where G is a constant, M and M the masses e d the distance betwen masses.

A single fixed pulley can be used to raise or lower lightweight objects.
Option b
<u>Explanation:</u>
A pulley is a simple machine tool which is used to make lifting or lowering tasks easy. A single fixed pulley is a system involving only one pulley fixed on a constant rigid support with a rope wrapped around the wheel. Such a system can be used only to change the direction of applied force in raising or lowering small, lightweight objects which need minimal work force.
A single fixed pulley system helps only in redirecting the applied force direction by using a rope and wheel assembly. The work done in such a case remains the same and hence it is not preferred to use it in lifting heavy objects. Neither is the required force reduced in case of a single fixed pulley system. A movable pulley helps in achieving (A) and (C).
Unequal opposite forces.
(They're unbalanced.)
Answer:

Explanation:
= Charge at 3000 m = 40 C
= Charge at 1000 m = -40 C
= 3000 m
= 1000 m
k = Coulomb constant = 
Electric field due to the charge at 3000 m

Electric field due to the charge at 1000 m

Electric field at the aircraft is
.
If you take mirrors, and set them up at precise locations and angles, you can see everywhere by looking in the starting mirror. It is AMAZING!