Question

A hypothetical planet has a mass 1.90 times that of Earth, but the same radius.

What is g near its surface?

Answer 1

Use that the force is \[F=G*m*m p/r ^{2}\] with G=6.67e-11, m the mass of your point and mp the mass of the planet.
Then consider you want your force to be some \[F=m*g\].
So : \[g = G*m p/r ^{2}\]

Answer 2

When I plug in my values I get:

\[6.673*10^-11Nm^2/kg^2*1.136kg/(6.38*10^3km)^2=1.86m/s^2\]

I must have gotten the wrong mass of the planet because its saying my answer is wrong. I did this to get the mass of the planet:

\[5.98*10^{24}*1.90=1.136kg\]

Answer 3

Is this the answer:

\[g=Gm _{p}/r^2(6.61*10^-11Nm^2/kg^2)(5.98*10^24kg)(1.1362*10^25)/(6.38*10^3km)^2\]=\[18.62g\]

Answer 4

nevermind the answer was 18.6m/s