Class: Date: Exam 3--PHYS 101-WWP--Fall 2013--Chapters 8, 9, & 10 Multiple Choice Identify the choice that best completes the statement or answers the question. 1. A vault is opened by applying a force of 300 N perpendicular to the plane of the door, 0.80 m from the hinges. Find the torque due to this force about an axis through the hinges. a. 240 N m b. 360 N m c. 120 N m d. 300 N m 2. Two identical bars are joined as shown and rotate about the dashed line. Which of these has the largest moment of inertia? a. a c. c b. b d. d 3. This figure shows an arrangement of 3 particles rotating about a common axis. The axis bisects the 2 kg mass. The 4 kg mass is 3 m from the axis, and the 5 kg mass is 2 m from the axis. What is the moment of inertia? 4. A horizontal 100.0 kg merry-go-round of radius 1.0 m is started from rest by a constant horizontal force of 50.0 N applied tangentially to the merry-go-round. Find the kinetic energy of the merry-go-round after 3.00 s. (Assume it is a solid cylinder.) a. 56 kg m 2 b. 24 kg m 2 c. 28 kg m 2 d. 22 kg m 2 a. 5000 J b. 10,000 J c. 900 J d. 230 J 1
5. What is the net torque acting on this bar about the point C? a. 12 Nm clockwise c. 59 Nm counterclockwise b. 19 Nm counterclockwise d. 67 Nm clockwise 6. A merry-go-round has a mass of 100 kg and a radius of 1m. It is spinning at 2 rev/s. A kid with a mass of 50 kg jumps onto the outer rim of the merry-go-round. What is the angular velocity of the merry-go-round after the kid jumps aboard? 7. Which state of matter is associated with the very highest of temperatures? a. gas b. solid c. plasma d. liquid 8. When you drink liquid through a straw, which of the items listed below is primarily responsible for this to work? a. atmospheric pressure b. mass of the water c. gravity d. inertia e. water pressure a. 0.5 rev/s b. 4 rev/s c. 1 rev/s d. 2 rev/s 2
9. A stonecutter's chisel has an edge area of 0.50 cm 2 (=5x10-5 m 2 ) If the chisel is struck with a force of 45 N, what is the pressure exerted on the stone? a. 450 000 Pa b. 90 000 Pa c. 9 000 Pa d. 900 000 Pa 10. Two beakers are filled to the brim with water. A wooden block is placed in beaker b so it floats. (Some of the water will overflow the beaker.) Both beakers are then weighed. Which scale reads a larger weight? 12. A blood platelet drifts along with the flow of blood through an artery that is partially blocked. As the platelet moves from the wide region into the narrow region, the blood pressure: a. increases b. decreases c. stays the same 13. A heavily loaded boat is floating in a pond. The boat sinks because of a leak. What happens to the surface level of the pond? a. More information is needed to reach a conclusion. b. It goes down. c. It stays the same. d. It goes up. 14. A solid rock, suspended in air by a spring scale, has a measured mass of 9.00 kg. When the rock is submerged in water, the scale reads 3.30 kg. What is the density of the rock? (water density = 1 000 kg/m 3 ) a. Beaker a b. Beaker b c. both the same weight 11. How deep under the surface of a lake would the pressure be double that at the surface? (1 atm 1 10 5 Pa; let g=9.8 m/s 2 ) a. 1.20 10 3 kg/m 3 b. 1.58 10 3 kg/m 3 c. 3.50 10 3 kg/m 3 d. 4.55 10 3 kg/m 3 15. Bernoulli s equation is based on which of these laws: a. Archimede s Law b. Conservation of Energy c. Conservation of Matter d. Conservation of Continuity a. 9.80 m b. 1.00 m c. 32.2 m d. 10.2 m 3
16. An ideal fluid, of density 0.90 10 3 kg/m 3, flows at 6.0 m/s through a level pipe with radius of 0.50 cm. The pressure in the fluid is 1.3 10 5 N/m 2. This pipe connects to a second level pipe, with radius of 1.5 cm. Find the speed of flow in the second pipe. 20. A steel wire, 150 m long at 10 C, has a coefficient of linear expansion of 11 10 6 /C. Give its change in length as the temperature changes from 10 C to 45 C. a. 0.33 m/s b. 18 m/s c. 0.67 m/s d. 54 m/s 17. The kelvin temperature scale is based, in part, on which of these temperatures: a. water s condensation temperature b. the triple point of water c. the freezing point of water d. freezing point of hydrogen 18. 88 F is how many degrees Celsius? a. 5.8 cm b. 0.65 cm c. 1.8 cm d. 12 cm 21. At room temperature, the coefficient of linear expansion for Pyrex glass is that for ordinary glass. a. less than b. more than c. stronger than d. the same as 22. Two moles of nitrogen gas are contained in an enclosed cylinder with a movable piston. If the molecular mass of nitrogen is 28, how many grams of nitrogen are present? a. 49 b. 158 c. 31 d. 56 19. Which of the following properties can be used to measure temperature? a. the color of a glowing object b. the volume of gas held at constant pressure c. the length of a solid d. all of the above a. 42 g b. 0.14 g c. 56 g d. 112 g 23. A rigid container has a volume of 0.1 m 3 and holds 10 moles of gas. If the gas is at a pressure of 1.5 atmospheres, what is the temperature of the gas in C? (The ideal gas constant is 8.314 J/(mol K).) a. C b. C c. C d. C 4
Exam 3--PHYS 101-WWP--Fall 2013--Chapters 8, 9, & 10 Answer Section MULTIPLE CHOICE 1. ANS: A PTS: 1 2. ANS: A PTS: 1 3. ANS: A PTS: 1 4. ANS: D PTS: 1 5. ANS: B PTS: 1 6. ANS: C PTS: 1 7. ANS: C PTS: 1 DIF: 1 TOP: 9.1 States of Matter 9.2 The Deformation of Solids 8. ANS: A PTS: 1 9. ANS: D PTS: 1 DIF: 2 TOP: 9.3 Density and Pressure 10. ANS: C PTS: 1 11. ANS: D PTS: 1 DIF: 2 TOP: 9.4 Variation of Presssure with Depth 9.5 Pressure Measurements 12. ANS: B PTS: 1 13. ANS: B PTS: 1 DIF: 2 TOP: 9.6 Buoyant Forces and Archimedes's Principle 14. ANS: B PTS: 1 DIF: 2 TOP: 9.6 Buoyant Forces and Archimedes's Principle 15. ANS: B PTS: 1 DIF: 2 TOP: 9.7 Fluids in Motion 9.8 Other Applications of Fluid Dynamics 16. ANS: C PTS: 1 DIF: 2 TOP: 9.7 Fluids in Motion 9.8 Other Applications of Fluid Dynamics 17. ANS: B PTS: 1 18. ANS: C PTS: 1 DIF: 1 TOP: 10.1 Temperature and the Zeroth Law of Thermodynamics 10.2 Thermometers and Temperature Scales 19. ANS: D PTS: 1 DIF: 2 TOP: 10.1 Temperature and the Zeroth Law of Thermodynamics 10.2 Thermometers and Temperature Scales 20. ANS: A PTS: 1 DIF: 2 TOP: 10.3 Thermal Expansion of Solids and Liquids 21. ANS: A PTS: 1 DIF: 1 TOP: 10.3 Thermal Expansion of Solids and Liquids 22. ANS: C PTS: 1 DIF: 1 TOP: 10.4 Macroscopic Description of an Ideal Gas 23. ANS: B PTS: 1 1