What is the ratio between times for the aliens to hit the floor. you have two spheres of equal density throughout. One has a radius R and the other 1/2R. An alien falls down one and takes time T, the other it falls down in time t. In the second on, time t, half of the mass of the ball is taken out and it only haas to fall down half of r to the center. What is the ratio between times?
i think 4(pie)r^2
The Attempt at a Solution
if the mass was the same, it would take a time ^2 betwen them as acceleration is squared due to gravity, so i think it would just be Ta^2:1/2T^2
i know this is wrong but im not sure how to go on