Download Exam 1 with Answer key - How Things Work | PHYS 140 and more Exams Classical Physics in PDF only on Docsity!
Name Discovery Room TA Section
Turn off your cell phone and put it away.
Please do not open this exam book until you are told to do so. You will need
- A #2 pencil
- One scantron answer sheet
- One exam question booklet
Instructions— This is a closed book exam. You have sixty (60) minutes to complete it.
- Use a #2 pencil; do not use a mechanical pencil or a pen. Fill in completely (until there is no white space visible) the circle for each intended input – both on the identification side of your answer sheet and on the side on which you mark your answers. If you decide to change an answer, erase vigorously; the scanner sometimes registers incompletely erased marks as intended answers; this can adversely affect your grade. Light marks or marks extending outside the circle may be read improperly by the scanner.
- Print your last name in the YOUR LAST NAME boxes on your answer sheet and print the first letter of your first name in the FIRST NAME INI box. Mark (as described above) the corresponding circle below each of these letters.
- Print your NetID in the NETWORK ID boxes, and then mark the corresponding circle below each of the letters or numerals. Note that there are different circles for the letter “I” and the numeral “1” and for the letter “O” and the numeral “0”. Do not mark the hyphen circle at the bottom of any of these columns.
- This Exam Booklet is Version A. Mark the A circle in the TEST FORM box at the bottom of the front side of your answer sheet. DO THIS NOW!
- Stop now and double-check that you have bubbled-in all the information requested in 2 through 4 above and that your marks meet the criteria in 1 above. Check that you do not have more than one circle marked in any of the columns.
- Do not write in or mark any of the circles in the STUDENT NUMBER or SECTION boxes.
- On the SECTION line , print your DISCOVERY ROOM. (You need not fill in the COURSE or INSTRUCTOR lines.)
- Mark only one answer per question.
- When told to do so: Check to make sure that the test booklet is complete. There are 11 numbered pages, including this cover sheet.
- If you understand the statement below, please sign (DO NOT PRINT) your name on the STUDENT SIGNATURE line. If you do not understand, please ask the professor for clarification.
Academic Integrity— Giving assistance to or receiving assistance from another student or using unauthorized materials during a University Examination can be grounds for disciplinary action, up to and including dismissal from the University
1 of 11 pages
- In class Prof. Perdekamp sat on a cart, pressed a fire-extinguisher, and shot across the floor. The momentum of Prof. Perdekamp after pressing the fire-extinguisher was ____ before pressing it.
a. greater than b. the same as c. less than d. the opposite of what it was
- You push your refrigerator with 100 lbs of force and the refrigerator slides across the floor at constant velocity. The net force on the refrigerator while it is sliding at constant velocity is
a. zero. b. more than zero but less than 100 lbs. c. exactly 100 lbs. d. more than 100 lbs. e. Can’t tell unless you know coefficient of friction.
- One of the universal laws of physics is that
a. mechanical energy is always conserved. b. total energy is always conserved. c. potential energy is always conserved. d. kinetic energy is always conserved.
- You’re driving along the highway and your windshield collides with a bug. Which of the following are true?
a. The force on the bug is the same size as the force on the windshield. b. The bug experiences greater acceleration than the windshield. c. The force on the bug is much greater than the force on the windshield. d. The car and bug experience equal acceleration e. Both a and b.
- A cook takes some pizza dough, shaped roughly like a plate, spins the dough and throws it in the air. The pizza dough spreads out (becoming a larger “plate”) in the air. As it spreads out, its spinning
a. speeds up. b. slows down. c. stays the same. d. stops completely.
2 of 11 pages
- You are on a ship moving at a constant horizontal velocity and holding a ball at your side. You suddenly drop the ball. Ignoring air resistance, the ball will land
a. in front of you. b. next to you. c. behind you.
- If the polar ice caps melt and the water flows to the equator, the moment of inertia of the earth (including its water)
a. increases. b. decreases. c. stays the same.
- Your car has a flat tire. You get out the jack, place it under the corner of the car, and begin to turn the crank that operates the jack. To make the car rise 1 cm, you must push the jack handle for a distance of 100 cm. Assuming that there is no friction in the jack and ignoring the weight of the jack itself, the work you do on the jack handle is
a. zero. b. equal to the work the jack does on the car. c. more than the work the jack does on the car. d. less than the work the jack does on the car but more than zero.
- A shipping company ships two boxes to the moon. Both boxes are measured on Earth, and are correctly labeled on Earth. One box is labeled as 1 Newton, and the other is labeled as 1 kilogram. When the boxes arrive on the moon, the customs inspector, who is located on the moon, checks the labels. The inspector reports that
a. the 1-kilogram box is labeled correctly but the 1-Newton box is not. b. the 1-kilogram box is not labeled correctly but the 1-Newton box is. c. both the 1-kilogram box and the 1-Newton box are labeled correctly. d. neither the 1-kilogram box nor the 1-Newton box are labeled correctly.
- The moment of inertia of a long thin solid rod of aluminum is maximum when it is spinning about an axis
a. down the center of the rod lengthwise. b. through the center of the rod, perpendicular to its length. c. through the end of the rod, perpendicular to its length. d. The moment of inertia is a constant, so A, B, and C are all equal.
4 of 11 pages
- After clearing the bar in the high jump, you land softly on a giant mattress. Landing on the mattress is much more comfortable than landing on a sand heap of equal size because
a. you transfer less momentum to the mattress in coming to a stop than you would have transferred to the sand heap in coming to a stop. b. the force that the mattress exerts on you to stop your descent is much less than the force that the sand heap would have exerted on you. c. you transfer more momentum to the mattress in coming to a stop than you would have transferred to the sand heap in coming to a stop. d. your velocity is less as you land on the mattress than it would have been if you'd landed on the sand heap.
- Suppose that you throw a ball upward into the air. After the ball leaves your hand, is there any force pushing the ball upward?
a. Yes, if the ball is going up, there must be a force pushing it up. b. Yes, the force from the Earth’s gravity. c. No d. Yes, the upward acceleration of the ball.
- Momentum (of a closed system) is conserved
a. only in an elastic collision. b. only in vacuum. c. only in outer space (without gravitation). d. always. e. only in the absence of any forces.
- A monkey - sitting on a branch of a very high palm tree - released a banana from her hand. After 5 seconds
a. banana’s acceleration is approximately 50 m/s^2. b. banana’s speed is approximately 50 m/s. c. banana fell approximately 50 meters. d. cannot tell until I know banana’s weight. e. banana’s acceleration is approximately 25 m/s^2.
- Catwoman hangs from a branch and with her cat vision sees a criminal, 300 meters away, shooting directly towards her. To save her life, at the very moment the gun is shot, she should
a. hang on. b. release her grip of the branch and fall.
5 of 11 pages
- A rock is dropped from a great height. Ignore air resistance. If the acceleration due to gravity is 10 m/s^2 , then after 3.0 s the rock's acceleration is
a. 3 m/s^2. b. 10 m/s^2. c. 30 m/s^2. d. 100 m/s^2.
- Impulse is
a. how energy is transferred. b. how momentum is transferred. c. how work is done. d. how torque is done.
- When you pull a tablecloth out from under a set of dishes it is possible to remove the cloth without disturbing the dishes because of
a. Newton’s First Law. b. Newton’s Second Law. c. Newton’s Third Law. d. the conservation of energy.
- You are at the county fair and you are trying to win a stuffed animal by knocking over a stack of heavy milk bottles with a projectile. You have a choice of four projectiles: a 1-kilogram beanbag, a 2-kilogram beanbag, a 1-kilogram superball and a 2-kilogram superball. Assuming that you can throw each of these projectiles at the same final speed, which one will be most effective at knocking over the milk bottles?
a. The 2-kilogram superball. b. The 1-kilogram beanbag. c. The 2-kilogram beanbag. d. The 1-kilogram superball.
7 of 11 pages
- A father of 6-month old twins is pushing his fully-loaded double stroller on a sidewalk and comes to the library. The entrance patio is 4 feet above the sidewalk. There are three paths up:
- steps; 2) a long, shallow ramp and; 3) a short, steep ramp. Ignoring effects of friction, which path should he choose so he exerts the least amount of force?
a. The steps. b. The long, shallow ramp. c. The short, steep ramp. d. He must exert the same amount of force to follow any of these paths.
- A cheerleader is given two batons: One silver and one gold, and is told that each has the same weight. He tries spinning each one and finds that the gold one is much more difficult to start and stop spinning. He correctly concludes that the gold baton, in comparison to the silver baton:
a. has more of its weight distributed towards the center. b. has more of its weight distributed towards the ends. c. that they cannot be of the same weight, and the gold baton must weigh more. d. that they cannot be of the same weight, and the gold baton must weigh less.
- A physics student decides to practice shooting paperclips with a rubber band (at 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.
- Your roommate’s car has a pair of “fuzzy dice” hanging by a string from its rearview mirror. These dice do a nifty job of indicating how the car is moving. For example, if the dice swing forward toward the car’s windshield while the car is on a level road, you know that the car is
a. accelerating backward. b. accelerating forward. c. traveling backward at a steady pace. d. traveling forward at a steady pace.
8 of 11 pages
- The total angular momentum of an object
a. remains constant in all circumstances. b. changes when a next external force acts on it. c. changes when a net external torque acts on it. d. may or may not change under the influence of a net external torque, depending on the direction of the torque.
- Bill and John are playing on a frozen lake. They are facing each other and with their hands, they push off against one another. Bill weighs 200 pounds and John weighs 180 pounds. The magnitude of Bill’s acceleration is
a. smaller than the magnitude of John’s acceleration. b. equal to the magnitude of John’s acceleration. c. larger than the magnitude of John’s acceleration. d. impossible to tell from the information given.
- On the Moon, gravity is about 6 times smaller than gravity on the Earth. Therefore on the Moon, the impulse required to stop a 5 kg ball traveling horizontally on a frictionless surface at 2 m/s is
a. 6 times larger than on Earth. b. the same as on Earth. c. 6 times smaller than on Earth.
- Granny, with a mass of 75 kg 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. 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. e. both a. and b.
- Which of the following devices on a car can be used to cause the car to accelerate?
a. The gas pedal b. The brake pedal c. The steering wheel d. a. and b. e. All the above
10 of 11 pages
- You walk in a given direction for 20 m during the first 5 seconds of a trip and then 15 m during the next 2 seconds. Your average speed is equal to
a. 8 m/s. b. 2 m/s. c. 5 m/s. d. -5 m/s.
- Suppose you do 1000 J of work on a 5 kg object, and all the work went into lifting it above the ground. How high above the ground will the object be when all the work has been done?
a. 100 m b. 5 m c. 20 m d. 1 m
- A baseball player balances a bat on his finger; the bat is laying sideways and not standing on end. The bat will balance
a. near the end of its handle. b. near the end farthest from the handle. c. at its middle. d. at its center of mass.
- Suppose you are riding a bicycle. If you want to waste as little energy as possible while the bike is in motion, what type of friction should exist between the bike and the road?
a. Static b. Sliding c. None d. Can’t tell
Check to make sure you have bubbled in all your answers.
Did you bubble in your name, exam version and network-ID?
11 of 11 pages
