A man weighs 650 N while on the surface of Earth. If he is transported to the planet Mythos, which has the same mass as Earth but a radius that is five times larger than Earth's, his weight would be
A) 16,250 N.
B) 3,250 N.
C) 650 N.
D) 130 N.
E) 26 N.

Question

Quizplus · Accepted Answer

Weight is directly proportional to the mass of the planet and inversely proportional to the square of the radius of the planet. Since Mythos has the same mass as Earth but a radius 5 times larger, the man's weight would be $ \frac{1}{5^2} = \frac{1}{25} $ of his weight on Earth, which is $ \frac{650}{25} = 26 $ N.

A Man Weighs 650 N While on the Surface of Earth