A 45.0 kg skater is skating down a hill on roller blades at a speed of 10.0 ms. What is the kinetic energy of the skater?

The kinetic energy of the skater is 2,250 Joules. This is calculated using the formula KE = 0.5 * mass * velocity^2, where mass = 45.0 kg and velocity = 10.0 m/s.