PHYS101 Sec 001 Hour Exam No. 3: Physics Problems - Prof. Robert Gowdy, Exams of Physics

Download PHYS101 Sec 001 Hour Exam No. 3: Physics Problems - Prof. Robert Gowdy and more Exams Physics in PDF only on Docsity! PHYS101 Sec 001 Hour Exam No. 3 Page: 1 PHYS101 Sec 001 Hour Exam No. 3 Page: 2 1 If the speed of an automobile increases by a factor of two, the distance that it takes to stop should increase by a factor of a. 2: b. 4. c. 9. d. 16: e. 3. 2 An electrical power plant a. destroys energy. b. creates energy. c. converts energy. 3 An automobile bumper jack moves the bumper up a distance of 0:01m (one centimeter) for every meter that the jack handle is moved downward. It is found that a force of 133N on the jack handle produces a lifting force of 10; 000N on the bumper. What is the efciency of this jack? a. 66%. b. 75%. c. 100%. d. 50%. 4 In a spacetime diagram with t the time and x the distance, all of the points on the space axis have a. x = 0. b. t = x = 0. c. t = x. d. t = 0. 5 The Michelson-Morely Experiment tested the predictions of a. Newton's theory of mechanics. b. the Aether theory of light propagation. c. Einstein's theory of relativity. d. Maxwell's theory of electromagnetism. 6 In comparison to Kepler's Laws of Planetary Motion, Newton's theory of Universal Gravitation predicted a. almost the same motions but with corrections. b. the same motions interpreted differently. c. a completely different set of motions. d. exactly the same motions. PHYS101 Sec 001 Hour Exam No. 3 Page: 5 18 Suppose that observers on Earth nd that an asteroid collides with the planet Mars at exactly the same time that a comet collides with the earth. If a spaceship ying from Earth toward Mars observes these catastrophes, it will calculate that a. both happen at the same time. b. Earth get hit before Mars does. c. Mars get hit before the earth does. 19 The force on a 5kg object in a gravitational eld whose magnitude is 4m/s2 is equal to a. 4N. b. 20N. c. 50N. d. 5N. e. 6N. 20 A 2kg rock is dropped from rest at a height of 30 meters above the ground. How much heat energy is generated when it hits the ground? a. 600J. b. 900J. c. 0. d. 60J. 21 Two spaceships travel, side-by-side, at nearly the speed of light (relative to the earth). Each ship sees the other just 0.1 light-years away in a direction perpendicular to their direction of motion. Each ship leaves a thin trail of gas as it travels. In a frame of reference at rest relative to the earth, the distance between the two gas trails will be a. 0.1 light years. b. less than 0.1 light years. c. more than 0.1 light years. 22 An aircraft carrier uses a catapult to launch airplanes from its deck. The catapult consists of a hook that runs along a slot in the deck. The airplane is attached to the hook and is pulled along the slot until it reaches take-off speed. Suppose that the catapult accelerates the plane at 5 times the acceleration of gravity (5 “g”s) and the take-off speed is 100m/s. How long must the slot in the deck be? a. 100m. b. 1000m. c. 1m. d. 10m. e. 200m. PHYS101 Sec 001 Hour Exam No. 3 Page: 6 23 A spaceship travels from the earth to a star that is 12 light years away. If the trip takes 13 years in earth time, how many years pass on board the ship? a. 6. b. 3. c. 2. d. 5. e. 4. 24 Suppose that two objects, each with the same mass, are accelerated from rest to the same velocity. The force that accelerates one object is much larger than the force that accelerates the other object but acts for a shorter time. The work done by the larger force is a. equal to the work done by the smaller force. b. smaller than the work done by the smaller force. c. larger than the work done by the smaller force. d. unrelated to the work done by the smaller force. 25 Suppose that a car and a truck are traveling at the same speed. If the truck has three times the mass of the car, then the truck's kinetic energy is a. nine times that of the car. b. eight times that of the car. c. four times that of the car. d. twice that of the car. e. three times that of the car. 26 In the following spacetime diagram, which letter is closest to the event with x = 2, t = 1? 27 Two spaceships y side by side at nearly the speed of light, separated by a distance of 186,000 miles (one light-second in other words) in their own reference frame. If radio messages are exchanged between the ships the clocks on board the ships will nd that each exchange is delayed by a round-trip travel time of a. more than 2s. b. 2s. c. less than 2s. d. an indeterminate amount of time. PHYS101 Sec 001 Hour Exam No. 3 Page: 7 28 Which of the following phenomena consist of electromagnetic waves travelling at the speed of light? a. gamma radiation b. beta rays. c. alpha rays. d. gravity waves. 29 In the aether theory of light, a pulse of light travels at 186,000 miles per second relative to a. the aether. b. any inertial reference frame. c. the source of the light. d. the observer of the light. 30 The starship Enterprise is travelling on impulse drive at 4/5 light speed. For every two minutes that pass on board the ship, a clock back on earth will read an interval close to a. two minutes. b. three minutes and twenty seconds. c. two minutes and ten seconds. d. two minutes and thirty seconds. 31 If Einstein were to draw a spacetime diagram in which the x0 and t0 axes represent a moving inertial frame, which of the following diagrams would he draw? 32 A complicated system of pulleys and gears is set up so that pulling down on an “input” rope by one meter causes an “output” rope to move upward by 1/5 meter. If a force of 10 newtons is applied to the input rope, how much force can the output rope exert? a. 2N. b. 10N. c. 5N. d. 50N.