Question

Determine the force the sun exerts on an object with a mass of 80.0 kg if that object is on the earth. What is the force exerted by the moon on the same object? What is the force the earth exerts on it?

Answer 1

Explanation:

The law of universal gravitation states that the force exerted between two bodies and separated a certain distance, is equal to the product of their masses and inversely proportional to the square of the distance, that is:

$F=\frac{GMm}{d^2}$

Here G is the universal gravitational constant.

So, the force exerted by the sun is:

$F_s=\frac{6.674*10^{-11}\frac{N\cdot m^2}{kg^2}(1.989*10^{30}kg)(80kg)}{(1.496*10^{11}m)^2}\\F_s=0.47N$

The force exerted by the moon is:

$F_m=\frac{6.674*10^{-11}\frac{N\cdot m^2}{kg^2}(7.35*10^{22}kg)(80kg)}{(3.84*10^8m)^2}\\F_m=2.66*10^{-23}N$

The force exerted by the earth is given by:

$F=mg\\F=80kg*9.8\frac{m}{s^2}\\F=784N$