Learning Activity 3.5 Portfolio A. 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/s) 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? B. What is the cost of operating a 100 W light bulb 4 hours a day for 6 days if the price of electrical energy is 5 c/kWh? C. How much power does Daniel produce if he transforms 2.4 kJ of chemical energy (in pizza that he ate that day) into kinetic energy and thermal energy in 12.5 s?