A student wants to find out the height of a vertical cliff.
She thinks that she can calculate this by dropping a heavy steel ball from rest at the top of the cliff and timing how long it takes to reach the ground below.
Explain how she could use this time measurement to find the height of the cliff.
It takes 2.8 seconds2.8\text{ seconds}2.8 seconds for the steel ball to fall from rest and hit the ground. What is the speed of the ball just before it hits the ground? (Take g=9.8 m/s2g = 9.8\text{ m/s}^2g=9.8 m/s2.)
Describe the motion of the steel ball as it falls. Assume it does not reach terminal velocity. Describe the forces acting on the ball, including their relative sizes and directions, and explain how they affect its motion.