Quiz 2 Due on Monday April 12 by midnight	Name________________
Dr. Walt Volland

Spring 1999 50 points

 Answer all three essay questions. 10 points each

1. Why do all measured numbers have an uncertainty? Use the ruler shown here to measure the pencil length.

How long is the pencil? Give the correct number of significant figures/digits.

 

 

 

2. Four experiments were done to determine density. The measurements are listed here. What is the average density of the material? Give the answer to the correct number of significant figures. Which have better precision, the mass measurements or the volume measurements? Would a block of this material float or sink in water. Justify your answers.

Mass	Volume
223.8 g	34.4 mL
223.6 g	35.4 mL
223.7 g	33.4 mL
223.1 g	36.5 mL

 

3. Average normal human body temperature is 37 ^oC. Heat loss occurs when a body is in contact with lower temperature materials. How many calories would be used by the human body to warm up ice cold water up to body temperature if a person drank a liter of ice water at 0 ^oC?

Remember specific heat for water = 1 calorie/g ^oC

Remember density for water = 1 g/mL ^oC

Heat (cal) = mass(g) x temperature change (^oC) x specific heat (cal/g ^oC)

Do you think a weight loss plan based on drinking ice water is very effective? Justify your answer.

 

 

 

 

Multiple choice worth 2 points each maximum of 20 points

1. Potential energy results from the motion of an object.

a. true

b. false

2. Which of the following sets of measurements shows the best precision?

a. 1180. , 1190, 1170.

b. 274. , 307., 321.

c. 24000, 25000, 22000

d. 0.0026 , 0.028 , 0.027

 

3. The value 4. inches² is the same as ______ cm². NOTE 1 inch = 2.54 cm

a. (4.)(1.0/2.54)

b. (4.)(2.54)

c. 4.(2.54)²

d. 4.(1000.)(2.54)²

e. (1/ 4.)(2.54)²

 

4. Precision measures the agreement between a measurement and an accepted value.

a. true

b. false

 

5. How many significant digits are in the measurement 105. meters?

a. 4

b. 5

c. 3

d. 2

e. 1

 

6. Which of the following is not correct?

a. cent- means multiply by 1/100

b. kilo- means multiply by 1000

c. milli- means multiply by 1/10000

d. mega- means multiply by 1000000

 

7. If you round off 87.587 to two significant digits the answer is

a. 90

b. 800

c. 87.59

d. 88

 

8. What is the lowest possible kelvin temperature?

a. minus infinity

b. zero

c. -273.16

d. 273.16

e. there is no lower limit

 

9. The result of multiplying out (265.)(80.003) will have ____ significant digits.

a. 3

b. 2

c. 8

d. 5

 

10. Which of the following is an example of a pure substance?

a. carbon dioxide

b. sea water

c. air

d. beer

 

11. It is rumored that Humpty Dumpty weighed approximately 8 ounces.

What is this in kilograms? Note 1.0 kilogram = 2.2 pounds; 16 ounces = 1 pound

a. 8 x 2.2 x 16

b. 8 x 2.2

c.

d.

e.