1. Calculate and compare the KE of a 60 g tennis ball at 150 mph with the KE of a 200 g softball thrown at 60 mph (miles per hour).
2. If 1 kWh of electricity costs 20 cents, how much would the energy of the softball cost?
3. If a round lightbulb (of any type) produces 5 W of visible light, what will be the intensity 3 m away from it?
4. A large powerplant produces about 1 GW of electricity. What is area of land (in square kilometers) receives 1 GW of sunlight? (On the MC portion of the exam you were asked what is the intensity of sunlight.)
5. If the efficiency of solar cells is 20%, what are of land do you need to cover with solar cells to produce 1 GW of power?