Instructions: Test I. Multiple Choice. Please WRITE THE LETTER before the number that corresponds the correct answer. 1. A space probe is launched into space from Earth's surface. Which graph represents the relationship between the magnitude of the gravitational force exerted on Earth by the space probe and the distance between the space probe and the center of Earth? C. Force Force Force Force Distance Distance Distance Distance 2. The diagram shows two bowling balls, A and B, each having a mass of 7 kilograms, placed 2 meters apart. What is the magnitude of the gravitational force exerted by ball A on ball B? B 7.00 kg 7.00 kg -2.00 m- a. 8.17 x 109 N c. 8.17 x 10-10 N b. 1.63 x 10 N d. 1.17 x 10-10 N 3. A 60-kg physics student would weigh 1560 N on the surface of planet X. What is the magnitude of the acceleration due to gravity on the surface of planet X? a. 0.038 m/s c. 9.8 m/s2 b. 6.1 m/s2 d. 26 m/s 4. Earth's mass is approximately 81 times the mass of the Moon. If Earth exerts a gravitational force of magnitude F on the Moon, the magnitude of the gravitational force of the Moon on Earth is a. 9F C. F b. F/81 d. 81F 5. An object weighs 100 newtons on Earth's surface. When it is moved to a point one Earth radius above Earth's surface, it will weigh. a. 25 N c. 100 N b. 50 N d. 400 N 6. A container of rocks with a mass of 65 kilograms is brought back from the Moon's surface where the acceleration due to gravity is 1.62 meters per second2. What is the weight of the container of rocks on Earth's surface? a. 65 N C. 105 N b. 394 N 7. A person weighing 785 newtons on the surface of Earth would weigh 298 newtons on the surface of Mars, What is the magnitude of the gravitational field strength on the surface of Mars? a. 2.63 N/kg b. 3.72 N/kg c. 6.09 N/kg Thinant To d. 9.81 N/kg 8. When Earth and the Moon are separated by a distance of 3.84 x 10" meters, the magnitude of the gravitational force of attraction between them is 2.0 x 1020 newtons. What would be the magnitude of this gravitational force of attraction if Earth and the Moon were separated by a distance of 1.92 x 108 meters? a. 5.0 x 10"9 N b. 2.0 x 1020 N c. 4.0 x 1020.N losing Distin d. 8.0 x 1020 N9. An astronaut weighs 8.00 x 10"N on the surface of Earth. What is the weight of the astronaut 6.37 x 105 m above the surface of Earth? a. 0.00 N c. 1.60 * 10'N b. 2.00 x 10'N d. 3.20 x 10'N 10. A satellite weighs 200 newtons on the surface of Earth. What is its weight at a distance of one Earth radius above the surface of Earth? a. 50 N c. 400 N b. 100 N d. 800 N 11. A flywheel stops in 15 seconds from a speed of 220 rpm. Compute the number of turns the flywheel makes before it stops. a. 27.5 turns c. 25.7 turns b. 172.8 turns d. 52.7 turns 12. A power screw is rotated at constant angular speed of 90 rpm by applying a steady torque of 15 N-m. How much work is done per revolution? a. 2.4 N-m/rev c. 15 N-m/rev b. 94.25 N-m/rev d. 6.28 N-m/rev 13. A rod of length L and of negligible mass is pivoted at a point that is off-center with lengths shown in the figure below. The figures show two cases in which masses are suspended from the ends of the rod. In each case the unknown mass m is balanced by a known mass, M, or Ma, so that the rod remains horizontal. What is the value of m in terms of the known masses? a. MIM c. MI Ma b. " (M) + Mz) d. WM,Ma 14. A 5-meter uniform plank of mass 100 kilograms rests on the top of a building with 2 meters extended over the edge as shown. How far can a 50-kilogram person venture past the edge of the building on the plank before the plank just begins to tip? 5m -2m a. 0.5 m c. 1.5 m b. I m d. 2 m 15. A solid disk flywheel has a diameter of 1.5 m, and a mass of 800 kg. What torque is needed to produce an angular acceleration of 100 revolutions per minute, per second? a. 3265 N-m b. 5236 N-m c. 2356 N-m d. 6325 N-m 16. Which of the following is the unit of mass moment of inertia? a. kg-m' b. kg/m c. kg d. N-m 17. The flywheel of an engine has a mass of 2000 kg and radius of gyration equal to 1 m. The average torque on the flywheel is 1200 N-m. Determine the angular acceleration of the flywheel. a. 0.60 rad/s' b. 60 rad/s' c. 36 rad/s d. 6 rad/s?18. If the pulley shown in the figure weighs 36 lb and W = 720 lb, find P to maintain equilibrium. a. 96 1b c. 76 lb b. 86 lb d. 66 1b 19. The weight W of a traveling crane is 20 tons acting as shown in the figure. To prevent the crane from tipping to the right when carrying a load P of 20 tons, a counterweight Q is used. Determine the value and position of Q so that the crane will remain in equilibrium both when the maximum load P is applied and when the load P is removed. P=20 tons W- 20 tone a. Q- 40 tons, x = 3ft c. Q- 20 tons, x = 6ft b. Q 30 tons, x = 6ft d. Q- 20 tons, x = 3ft 20. The cylinders in the figure have indicated weights and dimensions. Assuming smooth contact surfaces, determine the reactions at A, B, C and D on the cylinders. W- 200 1 W .400 lb K a. RA=346.4 1b Ra = 600 lb Rc = 400 lb RD = 346.4 1b b. RA=600 lb Re = 346.4 1b Rc = 400 lb RD = 346.4 lb C. RA-346.4 1b Ra = 400 lb Rc = 600 1b RD = 346.4 lb d. RA=346.4 lb Ra = 600 lb Rc = 346.4 lb RD = 400 lb