Posted by **Robert C** on Monday, January 18, 2010 at 6:27pm.

Paleontologists estimate that if a Tyrannosaurus rex were to trip and fall, it would have experienced an upward normal force of approximately 261,100 N acting on its torso when it hit the ground. Assume the torso has a mass of 3700 kg.

Assuming the torso is in free fall for a distance 1.37 m as it falls to the ground, how much time is required for the torso to come to rest once it contacts the ground?

I have determined the upward acceleration to be 60.75m/s2.

I am having trouble dterminign what equation to use.