# Gravity Physics

A spherical non rotating planet has a radius R and a uniform density $ho$ throughout its volume. Suppose a narrow tunnel were drilled through the planet along one of its diameters as shown in the figure below, in which a small ball of mass m could move freely under the influence of gravity. Let r be the distance of the ball from the center of the planet. Suppose the ball is dropped into the tunnel from rest at the planet's surface.

F. Write an equation that could be used to calculate the time it takes the ball to move from point P to the center of the planet.

SOLUTION MISSING: Unfortunately the author of this youtube video removed their content. You may be able to find a similar problem by checking the other problems in this subject. If you want to contribute, leave a comment with the link to your solution.## Related Problems

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