The potential energy of a ball at the top of a hill is 15,000 J. Two-thirds of the way down the hill, the potential energy is 5476 J. What is the ball's kinetic energy at that point?

You need to fill a basketball with air to play with it. you know that your pump expels air at a velocity of 6 cm/s. you know that the volume flow rate of air being pumped into the basketball is 103 cm^3/s. what is the diameter of your needle?