Question

Jupiter has a radius of about 11.0 earth radii, and a mass 318 times the earths mass. Estimate the gravitational field on the surface of Jupiter compared to that on earth. Show your work.

* I really need help please

Answer 1

There is a formula given for gravitational field which is related to the distance you are from the centre and the total mass of an object.
You could sub in a bunch of values into the formula and find exact value, but you also know gravity is 9.8 on earth. To simplify our work, we will deal with multiples only.
As mass increases, gravity increases linearly, so 318 times more gives us 9.8 x 318. Now we also need to account for the increase in radius, which is a square inverse proportion.
So the gravity will actually be
\[G(jupiter) = (9.8 * 318) / 11^2 = 25.755 m/s^2\]

Answer 2

The reason it says estimate is because gravity is actually affected by a variety of things, like the density of rock in a particular area of the planet, or your elevation, etc. Therefor 25.8 is simply an apporximation