1. A baseball bat has 120 J of kinetic energy as it hits a baseball (m = 0.145 kg). (a) If the baseball bat transfers 70 J of its kinetic energy to the baseball, what is the efficiencyoftheenergytransformation? (b) Find the speed of the baseball immediately after it has been hit.

2. When a 50.0 kg skier (initially at rest) skis down a ramp located on Mars (where the acceleration due to gravity is 3.711 m/s2) from a vertical height of 2.00 m, she attains a speed of 3.00 m/s. a) What is the skier's total mechanical energy at the top of the ramp? b) What is the skier's total mechanical energy at the bottom of the ramp? c) What is the percent efficiency of the ramp?

3. How much power does Daniel produce if he transforms 2.4kJ of chemical energy (in pizza that he ate that day) into kinetic energy and thermal energy in 12.5s?