Paleontologists estimate that if a Tyrannosaurus rex were to trip and fall, it would have experienced a force of approximately 260,000 N acting on its torso when it hit the ground.

Question 1
Assuming the torso has a mass of 3800 kg , find the magnitude of the torso's upward acceleration as it comes to rest. (For comparison, humans lose consciousness with an acceleration of about 7g .)

Question 2
Assuming the torso is in free fall for a distance of 1.21 m as it falls to the ground, how much time is required for the torso to come to rest once it contacts the ground?

So confused I thought about F=ma. and also N=wg or even F=m*a*9.81.

But so confused about what to do.

See:

http://www.jiskha.com/display.cgi?id=1253753793