Physics 161 Energy and the Environment
Discussion section Tuesday
4/8: Chapter 1
Please think about the following questions at end of the chapter, which
will
serve as a basis for discussion:
Ch. 1 (pp. 33-34): 1, 2, 4, 5, 7, 9, 12, 16, 19, 21
Any other topics relevant to Chapter 1 (population, limited resources,
etc.) that you wish to raise are welcome! We won't have time to
discuss all of them, but this serves to help us focus.
Homework 2. Due Monday, April 14, 2003
Please use separate sheet(s) for your answers.
Chapter 1.
1. Discuss the idea that the price of energy should reflect the true cost of replacing it. If the price does not reflect the cost of replacing it, why not?
2. Why is the energy use per capita in the world rising?
3. Suppose a national crisis were to take place, and it was mandated that every individual would have to reduce the amount of energy that he or she uses per year by 25%. What steps would you have to take as an individual to achieve this goal?
Chapter 2.
Questions:
1. List the energy conversions that occur when (a) riding a bicycle and (b) using a windmill to pump water.
2. What happens to the kinetic energy of an automobile as it rolls up an incline and stops?
3. If the acceleration of an object is not zero, can the velocity of an object be zero? Explain.
Problems:
1. To what height would a 2-kg object have to be raised such that its gravitational potential energy would be equal to the kinetic energy it would possess if it were moving at 3 m/s?
2. A cart of mass 20 kg, initially at rest, is pushed with a net force of 40 N on a flat surface. If the cart is pushed 5m, what is the final KE? What is the final velocity (assume no heat losses to friction)?
3. A ball of mass 0.5 kg is dropped from a height of 5m. What is the greatest velocity it will have just before hitting the ground? Does the mass of the ball matter?