Bell RingerName:2/20/2009

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Quiz Answers

1. List the SI unit used to List the SI unit used toexpress force. N express energy. J2. What is the symbol used What is the symbol usedto express density? to express density?3. What two symbols are What two symbols are toused express pressure? used to express force?Pa N5. Explain the relationship Explain the relationshipbetween energy and force. between pressure and force.J = N*m (energy=force (pressure=applied over some distance) force applied on some area)

3/mkg3/mkg

2/mN 2/* smkg

2/mNPa

Extra Credits

• Firewalkers can safely cross hot wooden coals. In ½ to 1 pages, explain the physics of why this is so.

• Hot air popcorn makers make use of a lot of different heat transfers before we have something to eat. In ½ to 1 pages, explain at least 4 separate heat transfers that occur. (hint: there are heat transfers occurring in the kernel)

Homework – Chapter 22

• Due Tuesday February 24.

Lab

• Activity to be performed in groups no larger than 3!

Sea Breezes

• During the daytime, the shore heats more quickly than the water– Air over the shore rises and the cooler (more dense)

air from the water replaces it– Wind direction is from water to shore

• During the nighttime, the water retains heat longer than the shore– Air over the water rises and the cooler (more dense)

air from the water replaces it– Wind direction is from shore to water