ENERGY CONVERSION AND CONSERVATION
Use pages 140-145 in your text to answer these questions.
1. What is Niagara Falls used for?
Converting the mechanical energy of falling water to electricity with a generator
2. What kind of energy is moving water? Most forms of energy can be converted from
one ______to another.
Mechanical; form
3. What kind of energy conversion occurs in toaster? What kind of energy conversion
occurs when you eat food?
Electric to thermal; chemical to mechanical
4. Describe the energy conversions that occur when you strike a match.
Mechanical to chemical to thermal (chemicals in the match chemically produce flame)
5. Describe the energy conversions that occur when you turn on a car engine?
Mechanical, electrical, chemical, mechanical
6. Explain how kinetic energy becomes potential energy when you juggle and vice versa.
Ball going up gains potential as it loses kinetic. Coming down it loses potential and gains kinetic
7. Explain energy conversion in a waterfall.
Water at top has high potential and less kinetic, as it hits the bottom it loses all potential and has maximum kinetic
8. Explain energy conversion in a pole vault.
Pole represents potential energy, when pole vaulter springs up potential energy is converted to kinetic.
9. Explain energy conversion in a pendulum.
Pendulum has 0 kinetic and maximum potential at end of swing. Pendulum has max kinetic and 0 potential at bottom of swing.
10. What does the law of conservation of energy state? Can energy be created or
destroyed?
Energy can be neither created nor destroyed; No, but matter and energy can be converted into one another.
11. A machines efficiency is always less than 100%. What causes this? What kind of
energy does friction create?
Friction; heat
12. What did Albert Einstein find about the relationship between matter and energy?
What is the name of his most famous theory?
Matter and energy can be converted backand forth; General Theory of Relativity
13. What is the difference between the law of conservation of energy and the concept of
conserving energy?
Law of conservation of energy states that matter & energy can be neither created nor destroyed. Conservation of energy is the idea that humans need to conserve energy resources, a limited quantity.
14. Einstein wrote that E=mc2. This famous equation says that an amount of mass (m)
can be multiplied by the square of the speed of light (c2)to produce energy (E). Try
the following problem: what is the energy produced in joules when 1 kg is multiplied
by the speed of light squared? c=3x108m/sec
E = mc2; E = 1 kg x (3 x 108 m/sec)2 = 1 kg x 3 x 1016 m/sec = 3 x 1016 joules
This problem is not really correct. The units used in this equation are not the ones an engineer would use, nor are all the variables in the equation presented, but it does represent the massive amounts of energy that can be liberated from a relatively tiny amount of matter.
One joule is the energy required to lift a hamburger one meter. How many
hamburgers could you lift one meter if you converted one kg of mass to energy?
3 x 1016 hamburgers could be lifted one meter, or 1 hamburger could be lifted 3 x 1016 meters!