2. Two masses are suspended by a string over the pulley in an Atwood's machine. One mass is 200 grams; the other is 100 grams. Ignoring friction and pulley moment of inertica, what is the acceleration of the heavier mass? a.) 0 m/s2

b.) 3.26 m/s2

c.) 6.52 m/s2

d.) 9.8 m/s2

e.) 14.7 m/s2

3. Which of the following pairs of masses would have the slowest acceleration on the Atwood's machine?

a.) 100 grams and 95 grams

b.) 100 grams and 50 grams

c.) 100 grams and 5 grams

d.) 100 grams and 0 grams

e.) 0 grams and 5 grams

4. You measure the acceleration of two masses attached to a string threaded over a pulley at 4.9 m/s2. Which of the following must be the value of the two masses?

a.) 0 grams and 300 grams

b.) 50 grams and 300 grams

c.) 100 grams and 300 grams

d.) 150 grams and 300 grams

5. You notice that the pulley being used in the lab has noticeable friction. What effect does this friction have on the acceleration of the masses?

a.) Friction makes the masses accelerate more slowly.

b.) Friction makes the masses accelerate more quickly.

c.) Pulley friction has no effect.

d,) The friction causes the masses to not move at all.

6. Two masses of 50 grams and 150 grams are set up on an Atwood's machine. The measured acceleration is 4.5 m/s2. How much force is friction exerting on the heavier mass?

a.) 45 N

b.) 0.45 N

c.) 0.040 N

d.) 0.060 N

7. Imagine a Atwood's machine with a "massive" string without weights attached. The experiments here used a light string, whose mass (compared to that of the weights) you ignored. Suppose that you moved the string so that unequal lengths were on each side of the pulley. What type of motion will you see when the string is released?

a.) no motion

b.) constant speed

c.) constant acceleration

d.) increasing acceleration

8. If the pulley is quite massive, how will your results be affected?

a.) faster acceleration due to flywheel effect

b.) slower acceleration due to inertia

c.) no acceleration (constant) speed due to moment of inertia

d.) acceleration slows and then stops at terminal speed

Alivestock company reports that the mean weight of a group of young steers is 1100 pounds with a standard deviation of 93 pounds. based on the model n(1100,93) for the weights of steers, what percent of steers weigh a) over 1050 pounds? b) under 1300 pounds? c) between 1150 and 1250 pounds?

The 10-kg double wheel with radius of gyration of 125mm about o is connected to the spring of stiffness k = 600 n/m by a cord which is wrapped securely around the inner hub. if the wheel is released from rest on the incline with the spring stretched 225 mm, calculate the maximum velocity v of its center o during the ensuing motion. the wheel rolls without slipping

1. a student believes that colder water makes fish swim faster. he sets up an experiment using different temperatures of water and measures the speed of the fish. (chapter 1 – page 9) a. what is the independent variable? b. what is the dependent variable? c. list two constants the student should have for this experiment. 2. convert 0.375 mg to grams. show your work with units in order to receive credit. (chapter 1 – page 16) 3. a race car drives one lap around a race track that is 500 meters in length. (chapter 2 – pages 45-46) a. what is the driver’s displacement at the end of the lap? b. how is his displacement different from the distance traveled? 4. how far does a car travel in 90 seconds if it is traveling at a speed of 55 m/s? show the appropriate equation from your textbook and show your work with units in order to receive credit. (chapter 2 – pages 46-47) 5. two cars, both with a mass of 500 kg, are traveling down a road. the first car has a velocity of 65 m/s east and the second car has a velocity of 85 m/s west. (chapter 2 – pages 54-55) a. calculate the momentum of both cars showing the appropriate equation from your textbook and your work with units in order to receive credit. b. which car has the larger momentum? explain how you know. 6. an airplane traveling at 60 m/s comes to a stop in 10 seconds. calculate the airplane’s acceleration. show the appropriate formula and show your work with units in order to receive credit. (chapter 2 – pages 57-58) 7. an individual has a weight of 735 newtons. what is the individual’s mass? show the appropriate equation from your book and show your work with the units in order to receive credit. (chapter 3 – pages 78-79) 8. in terms of newton’s first law of motion, explain why it is important to wear a seatbelt while riding in a car. (chapter 3 – page 86) 9. if you kick a tennis ball with 50 n of force and then kick a soccer ball with 50 n of force, explain the difference in their motion according to newton’s second law. (chapter 3 – pages 81-82) 10. describe how the velocity and acceleration of a skydiver changes as she falls from the plane back to the ground. (chapter 3 – pages 88-89) 11. a child is swinging on swing. describe what happens to both the kinetic energy and potential energy of the child as she swings up and down. (chapter 4 – pages 123) 12. driving to work one morning, you get a flat tire. when using the car jack, you apply 120 n of force to the jack and the jack in turn applies 2000 n of force to lift the car up. what is the mechanical advantage of the jack? (chapter 4 – page 111) 13. a temperature of a 50 kg block increases by 15°c when 337,500 j of thermal energy are added to the block. (chapter 5 – pages 141-142) a. what is the specific heat of the object? show the appropriate equation from your book and show your work with units. b. what is the block made of? use the chart on page 141. c. is this block a good material for insulators or conductors? 14. explain why gases make better thermal insulators than solids or liquids. give one example from the textbook of a thermal insulator that can keep you warm on a cold day. (chapter 5 – pages 147) 15. several days after a snowfall, the roofs of some homes on your street have almost no snow on them, while the roofs on other homes are still snow covered. assuming they have all received the same amount of sunlight, give one reason for this observation related to thermal energy and insulation. 16. if you purchased a string of lights, how could you determine if the lights were wired in series or parallel? (chapter 6 – pages 185-186) 17. what happens to the current in a device if the resistance is decreased but the voltage stays the same? (chapter 6 – pages 181-182) 18. you measure the voltage difference of a circuit to be 15 v and the resistance to be 675 ω. what is the current in the circuit? show the appropriate equation from your book and show your work with units. (chapter 6 – page 182) 19. explain why a magnet from your refrigerator could not be used to lift something as heavy as a car. (chapter 7 – pages 202-203)