physics assignment 25

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1. Is a current carrying wire electrically charged because of the electrons moving in it?

2. Which uses more power, a 120 volt vacuum cleaner using 10 Amps, or a 240 V drill using 3 Amps?

3. The batteries in the figure at the right (in the document found on canvas) are identical, and the lightbulbs are all identical. Each figure has a voltmeter connected across one light bulb. Rank the voltage readings from the smallest to the largest.

Look at the figure before responding

Smallest Largest

4. Incandescent light bulbs convert a relatively small amount of the energy that they use into light. What happens to the rest of the energy used?

5. Electrical devices connected in series all lose power if one device is disconnected. However, if they are connected in parallel, only the disconnected device loses power.

How are automobile headlights connected, Series or Parallel?

6. Two people who weigh the same walk up a flight of stairs. Nicole does it in 20 seconds and Bill does it in 30 seconds.

(A) Which person does more work? (B) Which person uses more power?

7. When a rifle with a longer barrel is fired, the force of the expanding gases acts on the bullet for a greater distance. What effect does this have on the speed of the emerging bullet?

8. When a jumbo jet slows and descends on approach to landing there is a decrease in its kinetic energy and its gravitational energy. If energy is conserved, where did it go?

9. A moving hammer drives a nail into a board. If the hammer were moving at twice the speed, how much deeper would the nail be driven into the board?

10. Why bother using a simple machine if it doesn’t reduce the energy a person would have to expend?