Velocity and Acceleration

The following are some true/false questions about velocity and acceleration. If the answer is false, correct the italicized word.

1. The ratio of change in distance over change in time is called the average velocity.
2. The symbol "v" represents acceleration.
3. The magnitude of the average-velocity vector is the quantity average distance traveled.
4. Automobile speeds are usually measured in miles per hour (mph), or kilometers per hour (km/h).
5. The quantity (v x t) represents the change in speed of an object during the time interval (t).

All answers must be submitted by Friday night at 12am.

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Chemistry and the Environment

While waiting in an airport for a plane, you overhear this statement: "It's paranoid and ignorant to worry about industry or agriculture contaminating the environment with their chemical wastes. After all, this stuff is just made of the same atoms that were already present in our environment." Take what you have learned from Chemistry and counter this argument.

This assignment is due on Monday, September 10th by midnight.

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Direct and Indirect Measurements

A metric ruler was used to measure the thickness of three different beans. The results are listed below.

Bean 1 - 0.5cm
Bean 2 - 0.47cm
Bean 3 - 0.39cm
Average - 0.45cm

Another way to measure the thickness of the beans is by using the volume of a cylinder method. The volume of 10 beans were taken using water in a graduated cylinder. The beans were then laid out on a table in a circle and the diameter taken. This was repeated 3 times with 10 different beans every time. The thickness of each bean was determined with the following equation: V=pi x r(squared) x h, in which the height of the beans equaled the volume of the beans divided by pi times the radius of the circle squared. The information is listed below.

Trial 1 - Vol = 40mL, Radius = 5.0cm, Height = 0.51cm
Trail 2 - Vol = 41mL, Radius = 5.2cm, Height = 0.48cm
Trail 3 - Vol = 38mL, Radius = 4.9cm, Height = 0.50cm
Average - Vol = 40mL, Radius = 5.0cm, Height = 0.51cm

1. Which measurement is a direct measurement?
2. Which measurement is an indirect measurement?
3. Which measurement gives the more accurate measurement of the thickness of the bean?
4. What are some sources of error in making the indirect measurement? How might they be reduced?
5. When might indirect measurements be useful?

This assignment is due on Monday, September 10th by midnight.

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