You are an explorer on a tiny planet with no atmosphere. You drop a coffee filter and find that it falls 2.0m in 1.6s. As you were approaching the planet, you measured the radius to be 1.8x10^6 m. What is the mass of the planet?
So I used the 2.0m and 1.6s to figure out the acceleration due to gravity of the planet (I got 0.781 m/s^2). Under the assumption that it's velocity went from 0 to 1.25m/s in 1.6s (I got the velocity by dividing the distance by the time). Also since there's no air resistance I didn't need to worry about that affecting the acceleration.
But, I'm a little lost on how to figure out the mass of the planet without the mass of the coffee filter or the force acting upon the coffee filter.
I thought i could use F= G(m1)(m2)/(absolute value r)^2
with d being the radius but what do I do if I don't know the masses or the force involved?
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