Concordia University

PHYS 273

LESSON 2

1)T or F: For the Law of Conservation of Energy work, we must turn off lights, heaters, etc. when we leave the house.

2.T or F: In an isolated system energy can be transformed from one form to another, but the total energy in the system must stay constant.

2. Clothes dryer consumes 2500W of energy. In 2s how much energy does the dryer use?
3. You lift a cat from the ground up to a shelf 2 meters above the ground. Which is a description of the energy flow?
4. A laser is powered by a battery and is used to heat up a spot on a piece of paper. What is the energy flow?
5. Which of the following is closest to being an isolated system?
6. You are camping & you start a wood fire & use it to boil some H2O in a pot. Flow of En?
7. Plants need light in order to grow. They use the process of photosynthesis for this. What is the energy transfer involved?
8. The Law of Conservation of Energy
9. T or F: In a system which is NOT isolated the total amount of energy must stay constant.
10. A ball is rolling down a hill and gaining speed. What is happening?
11. A chair is sliding across a rough horizontal floor. The chair starts with 100J of KE and slows down and comes to a stop. What happened to the KE of the chair?
12. T or F: If the total energy of a system increases this does not necessarily mean that energy was added to the system.
13. T or F: According to the Law of Conservation of Energy if solar panels use the sun’s energy in Arizona, then there will be less solar energy for us to use in Canada.
14. Which is not a unit of Power?
15. Your little sister drops a bag of candy on your head from the roof of your house. Right before it hits your head it is moving quickly. Describe the candy’s En, from roof to head.
16. T or F: Home appliances that produce heat tend to be low power.