Course Name: Physics 1 Student: Kwinda Netshitangani Course ID: SCIH035058 ID: J47865775 Submittal: 52 Progress Test 2 This Progress Test covers the course materials that were assigned in Units 3 and 4. Although the progress test is similar in style to the unit evaluations, the progress test is a closed-book, proctored test. You may not have access to notes or any of the course materials while you are taking the test. It is important that you do your own work. Select the response that best completes the statement or answers the question. You may use your calculator or scratch paper to work out solutions. ____ 1. An object that has kinetic energy must have a. b. c. d. ____ 2. A car is traveling at 100 km/s and skids four times as far as the same car at a different speed. What is that different speed of the car? a. b. c. d. ____ 3. 80 km/s 9.8 km/s 50 km/s 25 km/s What is one centripetal force exerted on stunt motorcyclist Daring Dana while she is riding on the inner vertical surface of a circular track? a. b. c. ____ 4. volume and acceleration. mass and velocity. speed and acceleration. elevation and mass. friction her weight the normal force If an object is in neutral equilibrium, and any displacement neither raises nor lowers its center of gravity, this object is considered to be a. b. c. d. unbalanced. balanced. increased in its mass. lower in its center of gravity. ____ 5. A collision is considered inelastic if a. b. c. d. ____ 6. A ball is thrown into the air with 100 J of kinetic energy, which is transformed to gravitational potential energy at the top of its trajectory. If it returns to its original level less than 100 J of kinetic energy, the ball encountered a. b. c. d. ____ 7. gravity the string the lady bug the can If Nellie Newton pushes an object with twice the force for twice the distance, she does a. b. c. d. ____ 9. air resistance. gravitational acceleration. a faster descent time. a decrease of its mass. A ladybug rests on the bottom of a tin can that is being whirled horizontally on the end of a string. Since the ladybug, like the can, moves in a circle, there must be a force on it. What exerts this force? a. b. c. d. ____ 8. there is deformation. the objects do not stick together. the objects that collide do not get warmer. there is no distortion of the objects. twice the work. the same work. four times the work. eight times the work. Rotational inertia times the rotational velocity is a. b. c. d. linear momentum. angular momentum. curved momentum. gravitational momentum. ____ 10. Any object thrown into the air with a spin rotates about its a. b. c. d. heaviest side. midpoint. center of mass. sharpest edge. ____ 11. Suppose you try loosening a nut with a wrench, and the nut doesn't give at all. To increase your chance of success, you will want to a. b. c. exert a smaller force. be sure to exert force perpendicular to the lever arm. shorten the lever arm. ____ 12. Efficiency is a. b. c. d. the ratio of output force to input force of a simple machine. the ratio of useful work output to total work input. the ratio of useful work output to input force. the ratio of output force to total work input. ____ 13. Compared to a sports car moving at 30 miles per hour, the same sports car has twice the momentum when moving at what speed? a. b. c. d. 15 miles per hour 30 miles per hour 45 miles per hour 60 miles per hour ____ 14. An example of neutral equilibrium is a. b. c. d. the downward motion of a thrown ball. the upward motion of a thrown ball. a ball rolling on the floor. a ball resting on the floor. ____ 15. Two jobs require the same work to complete, but one job is completed twice as fast. How much power is required for the job that is completed twice as fast? a. b. c. d. half as much power the same amount of power twice as much power four times as much power ____ 16. Watts and kilowatts are units of a. b. c. d. power. energy. force. momentum. ____ 17. A person weighs _______ at Earth’s poles than at its equator because of the ____________. a. b. c. d. more; influence of the moon less; spin of the Earth more; spin of the Earth less; lower temperature at the poles ____ 18. In physics, for a given object, work divided by net force will equal a. b. c. d. distance. time. impulse. velocity. ____ 19. Which rolls to the bottom of a hill more quickly, a car tire alone or the same tire mounted on a rim? a. b. c. d. the mounted tire, regardless of the individual weights of tire and rim the tire alone, provided it is as heavy as the rim the mounted tire, provided the tire is lighter in weight than the rim the tire alone, regardless of its weight ____ 20. A game room in a rotating space habitat is located in a 0.25 g region. If a person can jump 0.5 m high in a 1 g region, how high can the same person jump in the game room? a. b. c. d. 0.5 m 2m 4m 8m ____ 21. A ring, a disk, and a solid ball having equal masses roll down a hill at the same time. Which reaches the bottom in second place? a. b. c. the ring the disk the ball ____ 22. Which has greater kinetic energy, a car traveling at 45 km/h or a half-as-massive car traveling at 90 km/h? a. b. c. The 90 km/h car has greater kinetic energy. Both have the same kinetic energy. The 45 km/h car has greater kinetic energy. ____ 23. A 6 kg ball is thrown at 4 m/s. What is the ball's momentum? a. b. c. d. 4 kg·m/s 5 kg·m/s 10 kg·m/s 24 kg·m/s ____ 24. "Centrifugal force" is not a real force. a. b. True False ____ 25. If the planet Jupiter underwent gravitational collapse, its rate of rotation about its axis would a. b. c. d. decrease. increase. stay the same. More information is needed. ____ 26. Superman is at rest in space when he throws an asteroid that has more mass than he does. Which moves slower, Superman or the asteroid? a. b. c. d. Superman the asteroid They both move at the same speed. They both move in the same direction. ____ 27. When an ice skater pulls in his hands to turn faster a. b. c. angular momentum is not conserved. his momentum of inertia changes. his rotational speed does not change. ____ 28. A rock and a rubber ball have the same mass. If you drop them both from the top of a 3-story building, which object will produce a lesser impulse? a. b. c. d. The rock will produce a lesser impulse because it will dent the surface it hits. The rock will produce a lesser impulse because it will not bounce as high as the ball when it hits the ground. The rubber ball will produce a lesser impulse because it will bounce higher. The rubber ball will produce a lesser impulse because it will stop when it hits the ground. ____ 29. If you quickly go through the motions of throwing a small ball while standing on roller skates, but actually hold onto it instead, your net recoil velocity will be a. b. c. d. zero. the same as if you had thrown the ball. small but noticeable. negative. ____ 30. Nellie Newton swings a rock into a circular path while holding an attached string overhead. The string makes a 45-degree angle to the vertical (comprising a "conical pendulum"). The centripetal force vectors involved will include a. b. c. d. Nellie Newton’s height. air resistance. the tension in the string. the horizontal component of the string tension. ____ 31. What is the direction of the force that acts on clothes in the spin cycle of a washing machine? a. b. c. d. inward down outward up ____ 32. A pulley is a. b. c. d. fulcrum. inclined plane. complex machine. a lever that can be used to change the direction of a force. ____ 33. A space habitat has a radius of 200 m. If the average person is 2 m tall, then the habitat is designed so that the variation in g between a person's head and feet is a. b. c. d. less than 0.01 g. less than 0.1 g. more than 1.0 g more than 9.8 g ____ 34. An object that has kinetic energy must have all of the following except a. b. c. d. gravitational potential energy. mass. momentum. velocity. ____ 35. The long heavy tail of a spider monkey allows the monkey’s center of gravity to a. b. c. d. become its center of mass. easily change. decrease momentum. increase inertia. ____ 36. Energy is always changed from one form to another with a net gain or loss. a. b. True False ____ 37. In order to decrease the final momentum of a golf ball, you could a. b. c. d. decrease the force acting on it. follow through when hitting the ball. increase your swing speed. increase the time of contact with the ball. ____ 38. A person on a roof first throws one ball downward and then throws an identical ball upward at the same speed. The ball thrown upward goes up, then comes down and hits the ground with 140 J of kinetic energy. Ignoring air friction, with how much kinetic energy does the first ball hit the ground? a. b. c. d. 140 J/ 9.8m/s 140 J x 9.8 m/s 140 J 280 J ____ 39. When a wrench is slid spinning over a frictionless tabletop, its center of gravity follows a. b. c. d. a curved path with regular speed. a wobbly path with irregular speed. its center of mass moving in a regular straight-line path. a straight-line path with irregular speed. ____ 40. A woman can roll barrels up a 2 m ramp with an applied force of 1/2 as much as if she can lift barrels a vertical distance. What is the vertical distance? a. b. c. d. 4m 3m 2m 1m ____ 41. When you carry a heavy load with one arm, why do you tend to hold your free arm away from your body? a. b. c. d. to change the mass of your body to be ready to grab something in case you fall to change the weight of your body and the load to change the center of gravity of your body and the load ____ 42. Which has more rotational inertia, a girl spinning with one leg extended or the same girl spinning with both her legs straight? a. b. c. d. A girl spinning with one leg extended. A girl spinning with straight legs. Both have the same rotational inertia. Leg extension doesn't affect rotational inertia. ____ 43. Sue can easily lift a 45.0 N rock with the help of a lever. When she pushes down with 20.0 N of force, she moves her arms 0.675 m. How far is the rock lifted? a. b. c. d. 0.1 m 0.2m 0.3 m 0.4 m ____ 44. A cannon fires a cannonball. If the speed of the cannonball is the same as the speed of the recoiling cannon, then a. b. c. d. the mass of the cannonball equals the mass of the cannon. momentum is conserved. velocity is conserved. both velocity and momentum are conserved. ____ 45. Which answer does NOT explain why padded dashboards are used as a safety feature in cars? a. b. c. d. They decrease the deceleration. They decrease the force of impact. They increase the force of impact in a collision. They increase the time of impact in a collision. ____ 46. 40 J of work is done on a crate that you lift 2 m, what is the net force of the crate? a. b. c. d. 40 N 30 N 20 N 10 N ____ 47. The weight times the height of an object equals its a. b. c. d. density. size. speed. gravitational potential energy. ____ 48. A good explanation of why a ball would lose speed as it rolls down an incline involves a. b. c. d. the increase of a force that acts on it. increasing the friction between it and the incline. the additional torque that acts on it. the concentrated rotational inertia of the ball. ____ 49. If Earth rotated more quickly about its axis, your weight would a. b. c. d. decrease. increase. stay the same. equal your weight on the moon. ____ 50. As the rotational speed of a space habitat increases, the weight of people inside a. b. c. d. decreases. increases. stays the same. is one-half the space habitat’s center of gravity. Carefully review your answers on this progress test and make any corrections you feel are necessary. When you are satisfied that you have answered the questions to the best of your ability, transfer your answers to the online test submission page in the presence of your proctor. 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