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Physics 100 Midterm GRADE OR EDUCATION = 1 SPECIAL CODE = 2 February 10, 2011 NAME__________________________________________________ (CLEARLY PRINT YOUR NAME HERE - YES, you MUST do this. This paper will not leave my custody, printing your name here is your proof that you took this exam should anything happen to your scantron while it is out of my hands.) QUESTIONS ARE ON FRONT AND BACK OF THE EXAM!!! You may write as much as you want on this exam. BEFORE YOU BEGIN: 1. Put away all books, papers, cellphones and iPods. They should be completely underneath the desk. You should have nothing on your desk except a pencil or pen, 3x5 card, calculator, scantron and this exam. 2. Bubble in your name LAST NAME FIRST. 3. Bubble in your Grade or Education as shown above. 4. You have the entire class period to take this exam. Take your time, read the questions carefully. 5. Answer all questions. Make an educated guess if you don’t know the answer. 6. Do NOT cheat. If you look to a neighbor for answers, if you have a hidden study sheet, if you have any other way of cheating that I haven’t thought of yet, this exam will be taken away from you and at the very least you will get a score of zero. You could fail the class. It is your responsibility to make sure you understand the question before attempting it. Assume ideal conditions unless otherwise stated. Physics 100 Midterm Feb. 10, 2011, Special code #2 Name___________________________________ Student ID Number __________________________ MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) The force needed to maintain a body at constant speed in outer space [far from all outside influences] is equal to A) the force required to stop it. B) the mass of the body. C) zero. D) the weight of the body. E) the density of the body. 1) 2) One joule is the same as one A) newton-meter. B) newton-second. C) watt-meter. D) kilowatt-hour. E) meter per second squared. 2) 3) A stationary firecracker explodes, breaking into two parts of equal mass. One part is moving north at 20 m/s. The velocity of the other part is A) 20 m/s with a direction that's impossible to predict without more information. B) also northward at 20 m/s. C) southward at 20 m/s. D) impossible to predict without more information. E) zero. 3) C 4) A pool ball moving at 3 m/s collides head-on with an identical pool ball that's initially at rest. Just after the collision, the second ball moves away at 2 m/s while the first ball A) moves at 1 m/s in a direction opposite to the second ball. B) moves at 1 m/s in the same direction as the second ball. C) is at rest. D) moves at 3 m/s in a direction opposite to the second ball. E) continues moving at 3 m/s in the same direction. 4) B 5) "Energy" could best be defined as A) the ability to do work. B) the ability to exert power. C) the amount of force a system is capable of exerting. D) stored momentum. E) matter in motion. 5) 6) Forces of 8 N and 3 N act on an object. If the two forces act in opposite directions, the net force on the object is A) 11 N. B) 8 N. C) 5 N. D) zero. E) impossible to determine. 6) 1 C A A C 7) A ball is moving at 20 m/s. If no forces act on it, then 5 seconds later the ball's speed will be A) less than 20 m/s, but the precise answer cannot be found without further information. B) 20 m/s. C) more than 20 m/s, but the precise answer cannot be found without further information. D) zero. E) None of the above. 7) B 8) Ignoring air friction, while a rock is falling straight down it has A) an increasing acceleration. B) a constant [or unchanging] acceleration. C) a decreasing acceleration. D) zero acceleration. E) a constant [or unchanging] velocity. 8) B 9) A physics professor pushes against a stationary wall, "working" up a sweat. Is he doing any actual physical work on the wall? A) No--it's a law of nature that physics profs never do any actual work. B) No, because the force by his hands against the wall is balanced by the force by the wall pushing back. C) Yes, because he is exerting a force against the wall during a period of time. D) Yes, because his arm muscles are moving other muscles through a distance. E) No, because the wall is not moving. 9) 10) In comparing two waves of the same type and same amplitude, the one with the longer wavelength would have A) both higher energy and higher frequency. B) both higher energy and lower frequency. C) higher energy. D) higher frequency. E) lower frequency. 10) 11) 11) What form(s) of energy does the falling rubber ball have when it is halfway down (see figure)? A) Kinetic and gravitational and elastic B) Elastic only C) Kinetic only D) Kinetic and gravitational potential E) Gravitational potential only 2 E E D D 12) Which of the following is the basic [and most accurate] meaning of "mass"? An object's "mass" is A) the force exerted on it by gravity. B) the number of atoms it contains. C) the amount [or quantity] of matter it contains. D) a measure of its inertia. 12) 13) A ball is thrown straight upward. In the instant that it reaches the top of its motion and stops moving upward and begins to move downward, its acceleration is A) 9.8 m/s2 downward. 13) A 14) A 2000 N car travels 50 m along a level road, powered by a drive force of 1000 N. The work done by the drive force is A) 50,000 J. B) zero. C) 10,000 J. D) 1000 J. E) 2000 J. 14) A 15) Suppose you slowly, and at constant speed, lift a book weighing 7 N from the floor to a shelf 2 m above the floor. Neglect air resistance. The work done by you on the book is A) 6 joules. B) zero. C) 14 joules. D) 24 Newtons E) 6 Newtons 15) 16) Now suppose the 7N book that you lifted 2m to a shelf fell. What would be its Kinetic Energy just before it hit the floor? A) 14 Joules B) 140 Newtons C) zero D) 137 kilograms 16) 17) Suppose you are on the moon and you drop a rock and a feather at the same time. You will find that A) the two fall at the same speed, and this speed is the same as the speed of a rock falling on Earth. B) the rock falls faster than the feather, although both of them fall slower than they would on Earth. C) the two hit the surface of the moon at the same time. D) the rock falls faster than the feather, and both speeds are the same as they would be on Earth. E) they don't fall--they remain suspended above the surface of the moon. 17) C 18) The most characteristic feature of science is A) its precise quantitative observations. B) that Dr. Usher is always correct. C) that all scientist always agree on everything. D) the fact that scientific laws are absolutely true, i.e., that they have no exceptions. E) the mutually-supporting relationship between theory and experimental observations. 18) E B) zero. C) 9.8 m/s2 upward. D) unknown. E) extermely large. 3 C A 19) The type of energy that a swinging pendulum has at the high point of its swing is A) kinetic. B) thermal. C) gravitational potential. D) elastic. E) spring potential 19) C 20) The type of energy that a swinging pendulum has at the low point of its swing is A) sexual. B) thermal. C) kinetic. D) gravitational. E) elastic. 20) C 21) According to Newtonian physics, an object with no forces acting on it must A) either be at rest or have constant velocity. B) be accelerated, with an unchanging acceleration. C) eventually come to rest. D) fall. E) be at rest. 21) A 22) 22) B The graph depicts the motion of a mass bouncing on a spring. What is the period of the oscillation? A) 3 [meters] B) 5 [seconds] C) 7.5 [meters per second D) 0.2 [Hertz] 23) Still referring to the graph depicting the motion of a mass on a spring, What is the amplitude of the oscillation? A) 3 [meters] B) 5 [seconds] C) 6 [meters per second] D) 5 [seconds] 4 23) A 24) Consider the accompanying graph of speed verses time. What is the acceleration at 2 seconds? A) impossible to determine from this graph B) 0.5 [meters] C) zero [meters per second] D) 1 [meters per second squared] 25) Still refering to the graph of speed versues time, how far did the object travel during the time between 2 seconds and 3 seconds? A) impossible to determine from this graph. B) zero [meters] C) 0.5 [meters] D) 1 [metes per second squared] 5 24) D 25) C