Question

1. An Olympic diver has a kinetic energy of 12,000 J just prior to
    hitting the water. If the diver’s mass is 40 kg, then what is the
    speed of that diver?

2. A ball sits at the top of a stairway that has five steps. If the
    stationary ball at the top step has a PE of 50J, what is its PE at each
    of the following positions?

3.  If the ball in problem 2 is at the base of the same steps, what
     would the potential energy of it be?
     _________Joules at the base of the steps

Answer 1

1) Let the speed of the diver is v.

The mass of the diver is m=40 kg.

The kinetic energy of the diver is E=12000 J.

We know from the kinetic energy formula

  

  

  

The speed of the diver is 24.49489743 m/s or 24.49 m/s approximately.

2) Let the height of the stairway is h.

Let the mass of the ball is m.

From the gravitational potential energy

The potential energy at the top or 5th step is 50 J.

    The potential energy at the top or 4th step is

  

  

  

   The potential energy at the top or 3rd step is

  

  

  

  

   The potential energy at the top or 2nd step is  

  

  

   The potential energy at the top or 1st step is  

3)

  If the ball in problem 2 is at the base of the same steps, the potential energy of it be 0 J.