Download 45 MCQs on How Things Work in Physics - Examination 1 | PHYS 140 and more Exams Classical Physics in PDF only on Docsity!
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Page 1 of 11 pages
- You are riding a bicycle, and you slam on the brakes to avoid being hit by a car. Which of the following is true?
A. The bike’s velocity is forward, and its acceleration is forward. B. The bike’s velocity is forward, and its acceleration is backward. C. The bike’s velocity is backward, and its acceleration is forward. D. The bike’s velocity is backward, and its acceleration is backward.
- Suppose that you flip a quarter into the air. After the quarter leaves your hand, is there any force pushing the quarter upward? Neglect the effects of air resistance.
A. Yes, the same “fictitious force” we will learn about when we study roller coasters. B. Yes, the force from the Earth’s gravity pushes on the quarter. C. No D. Yes, the air underneath the quarter pushes it upward.
- In a basketball game, one of the players takes a full-court shot and throws the ball from one end of the court to the other. Ignore the effect of air resistance. At the highest point of the ball’s flight, the vertical component of the ball’s velocity is
A. up. B. zero. C. down. D. Not enough information is given to determine.
- Homer Simpson is fighting a robot. When Homer punches the robot and exerts a force on it,
A. the robot pushes on Homer with an equal force. B. the robot pushes on Homer with less force, since Homer threw the first punch. C. the robot does not exert a force on Homer, since Homer punched the robot. D. the robot pushes back on Homer with more force, since the robot is made out of metal.
- The earth enters an Ice Age, and water moves from the equator of the earth to the poles and freezes. The moment of inertia of the earth, including the water,
A. increases. B. decreases. C. stays the same.
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- When you are standing on the floor, the floor pushes on you with a force that is
A. more than your weight. B. equal to your weight. C. less than your weight. D. determined by friction.
- When you ride on a carousel or a merry-go-round, your velocity is
A. constant, since you go around in a circle at constant speed. B. always changing, since the direction of your motion is always changing. C. increasing, since you are accelerating toward the center of the carousel. D. decreasing, because friction is holding you on the carousel.
- In your car, there is a headrest at the top of your seat to help protect you. The headrest is most important when
A. you are moving forward and crash into a tree. B. you go around a turn too quickly and your car rolls over. C. you are stopped and another car hits you from behind. D. you hit a patch of ice and your car continues to move forward at constant velocity.
- When you drive in Colorado in the Rocky Mountains, there are some very steep downhill roads. On these roads you’ll notice “runaway ramps” for trucks. If a truck’s brakes fail, the driver can steer her truck onto one of these steep, uphill ramps. As the truck rolls up the ramp, it slows down because
A. kinetic energy of the truck is converted into gravitational potential energy. B. the total force of gravity on the truck is stronger when the truck is on the runaway ramp. C. the total force of gravity on the truck is weaker when the truck is on the runaway ramp. D. there is always less snow on an uphill slope compared with a downhill slope.
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*14. An astronaut on the space station, where there is no gravity, does acrobatics. When the astronaut doing somersaults and not in contact with the space station, which of the following quantities remain constant for the astronaut? Neglect the effects of air resistance, and choose the most complete answer.
A. velocity B. angular velocity C. momentum and angular momentum D. velocity, momentum, angular velocity, and angular momentum
- You are bouncing up and down on a springboard, preparing to dive into the pool. While you are in the air above the board, your acceleration is
A. zero because you are not touching anything. B. upward and constant until you reach the peak, then it becomes downward and constant. C. downward and constant. D. initially upward but it gradually diminishes to zero as you reach the peak and then it gradually becomes more and more downward.
- An object naturally spins about its
A.. moment of inertia. B. center of percussion. C. center of mass. D. lever arm
- Work is
A. how energy is transferred. B. how momentum is transferred. C. a measure of force. D. how torque is done.
- The force that keeps a car moving in a circle around a curve in the road is a
A.. force that points towards the center of the circle. B. force that points away from the center of the circle. C. force that always points up. D. force that always points down.
Page 5 of 11 pages
- A satellite is orbiting around the Earth in a circle at constant speed. Which of the following statements is correct?
A. The satellite’s velocity is constant, but its acceleration is not constant. B. The satellite’s velocity is not constant, but its acceleration is constant. C. The satellite’s velocity is not constant, and its acceleration is not constant. D. The satellite’s velocity is constant, and its acceleration is constant. E. Not enough information to tell.
- Julie decides to move ten identical books from the lower shelf of her bookcase to the upper shelf of her bookcase. If she were to move all the books together at once, she would do less work than if she were to move all the books one by one.
A. True B. False
- A 600kg car accelerates at 10 m/s^2. The net force on the car is equal to
A. 300 N B. 600 N C. 1000 N D. 3000 N E. 6000 N
*27. Arnold goes to see his grandpa in his old house. Arnold’s grandpa has an old piano sitting in the middle of his old Persian carpet in his living room. Arnold’s grandpa wants to get rid of the piano, so he asks Arnold to move it. He knows Arnold is very, very strong. If Arnold wants to minimize the force he needs to use in order to start the piano moving across the living room, he should apply
A. a force that is exactly horizontal. B. a force that is slightly downward. C. a force that is slightly upward. D. a force in any direction he wants; it will not matter. E. not enough information to tell. Correct answer should have been: “A force that is horizontal with a slight upward component”.
- A car skids to a stop. What happens to its kinetic energy?
A. It turns into potential energy of the tires. B. It turns into thermal energy. C. It disappears without a trace. D. Nothing: the car still has it, but it is just inactive.
Page 7 of 11 pages
- It’s freezing cold outside. Your car doesn’t want to start, so you decide to push it. You apply a horizontal force of 200 N to your car, but it doesn’t move at all. Which of these forces might have a magnitude different from 200 N?
A. the horizontal component of the frictional force exerted by the road on the car B. the horizontal component of the force exerted by the car on you C. the vertical component of the force exerted by the road on you
- Granny, with a mass of 75 kg a.bout 165 lbs. on earth) is skating along at 10 meters/sec and runs into Peewee, who has a mass of 25 kg and was just standing there. To avoid running him over, she picks him up and coasts, holding him in her arms. Ignoring the effects of friction, Granny and Peewee’s
A. total momentum is conserved. B. total kinetic energy is conserved. C. total velocity is conserved. D. total impulse is conserved.
- A physics student decides to practice shooting paperclips with a rubber band a.t the wall, of course). She correctly concludes this is an example of
A. conversion of elastic potential energy into kinetic energy. B. conversion of elastic momentum into kinetic momentum. C. conversion of elastic force into dynamic force. D. conversion of elastic angular momentum into linear momentum.
- When a modern car crashes into a tree and comes to an abrupt stop, the driver's face and chest collide with an air bag rather than with the steering wheel. The driver's chances of serious injury are reduced by hitting the air bag rather than the steering wheel because the driver transfers
A. less momentum to the air bag than he would to the steering wheel. B. the same amount of momentum to the air bag as he would to the steering wheel, but he does it with larger force due to the air bag. C. more momentum to the air bag than he would to the steering wheel. D. the same amount of momentum to the air bag as he would to the steering wheel, but he does it with smaller force due to the air bag.
Page 8 of 11 pages
- You are riding a skateboard down a gradual incline. In order to waste as little energy as possible while still maintaining control over your direction of motion, the contact between the sidewalk and the wheels should experience
A. only static friction. B. no friction. C. both static and sliding friction. D. only sliding friction.
- A torque acting on an object will produce a
A. change in equilibrium. B. change in rotational motion. C. change in linear motion. D. change in center of gravity.
- It’s December in Illinois, and the snow has started falling. There is some junk in the back of your pickup truck. In order to increase the force of friction between the tires of your car and the slippery roads, you should
A. throw more junk in the back of your truck to increase the weight of the truck. B. switch out all of the junk for an equal mass of sand, since the sand will increase the momentum of your car. C. remove all of junk from your truck, since the car will be easier to turn once it is lighter. D. do nothing, since the force of friction will be independent of the weight of your truck.
- A circular saw uses a spinning, circular blade to cut through wood. When you start the motor, it applies a constant torque and spins up the blade to its full angular velocity in 2 seconds. If you change the blade for one with three times the moment of inertia, how long with the motor now take to spin up the blade?
A. 2/3 seconds B. 1 second C. 2 seconds D. 6 seconds E 10 seconds
Page 10 of 11 pages
- You find that when you load up the door to your refrigerator with bottles of soda, the door becomes relatively hard to open or shut. It doesn’t respond quickly to your pushes or pulls. To minimize this effect, you should put the soda bottles as close as possible to the
A. bottom of the door. B. outside edge of the door a.way from the hinges). C. inside edge of the door (near the hinges). D. top of the door.
- The right end of a see-saw accelerates upward, as you view it. By the right-hand rule, the torque on the see-saw is
A. away from you. B. toward you. C. down. D. counterclockwise.
- You are driving your car at 60 miles/hour on highway 74. You enter a speed zone, and quickly decelerate to 30 miles/hour. The kinetic energy of your car
A. is four times smaller. B. is half as much. C. stayed the same. D. quadrupled (increased by four times).
- You weigh 150 pounds, and your friend is dragging you on a sled up a hill by pulling on a rope with 50 N of force. You are moving in a straight line and at constant speed. Your acceleration is
A. 1/3 m/s^2 B. 3 m/s^2 C. 50 N D. 0
- CREDIT IS GIVEN FOR ANY ANSWER FOR PROBLEMS 14 and 27 AND FOR BOTH ANSWERS B and D in PROBLEM 37
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