Question

An imaginary planet has mass 5 times and radius 3 times that of earth.What is the accelaration due to gravity on the planet, if the accelaration due to gravity on earth on earth is 10 m/ssquare?

Answer 1

Let M be the mass of earth and r be the radius
We know that, g = GM/ R2=10m/s2²
mass of unknown planet is Mp=5M
radius of Unknown planet is Rp=3R

Therefore, gp (acceleration due to gravity of unknown planet)
gp =
GMp/Rp²
=G (5 M)/(3R)²
gp = 5GM/ 9R2
or, gp = (5/9)g = 5.6 m/s2