Question

a new planet is discovered that has twice the earth’s mass and twice the earth’s radius. on the surface of this new planet, a person who weighs 500 n on earth would experience a gravitational force of

Answer 1

Answer: 250n

Explanation:

The formula for gravitational force is: F = (gMm)/r^2

There are two factors at play here:

1) The mass of the planet 'M'

2) The radius 'r'

We can ignore the small M and the g, they are constants that do not alter the outcome of this question.

You can see that both M and r are double that of earth. So lets say earth has M=1 and r=1. Then, new planet would have M=2 and r=2. Let's sub these two sets into the equation:

Earth. F =  M/r^2 = 1/1

New planet. F = M/r^2 = 2/4 = 1/2

So you can see that the force on the new planet is half of that felt on Earth.

The question tells us that the force on earth is 500n for this person, so then on the new planet it would be half! So, 250n!