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

What is g near its surface?

Question

A hypothetical planet has a mass 1.90 times that of Earth, but the same radius.

What is g near its surface?

anonymous · Answer

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 : $$g = G*m p/r ^{2}$$

anonymous · Answer

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:

$$5.98*10^{24}*1.90=1.136kg$$

anonymous · Answer

Is this the answer:

$$g=Gm _{p}/r^2(6.61*10^-11Nm^2/kg^2)(5.98*10^24kg)(1.1362*10^25)/(6.38*10^3km)^2$$=$$18.62g$$

anonymous · Answer

nevermind the answer was 18.6m/s