Physics Past Paper Review Test 3 PDF

Review and Practice - Physics Review topics for Newton’s Laws and Forces Unit Test Newton’s 3 laws of motion. Understand the meaning of each. Be able to use them in order answer questions or explain phenomenon 1. An object in motion will remain in motion at a constan...

Review and Practice - Physics Review topics for Newton’s Laws and Forces Unit Test Newton’s 3 laws of motion. Understand the meaning of each. Be able to use them in order answer questions or explain phenomenon 1. An object in motion will remain in motion at a constant speed in a straight line unless a force acts on it. 2. The acceleration of an object is directly proportional to the net force acting upon it and inversely proportional to its mass: Fnet = ma. 3. If object A exerts a force on object B, then object B exerts an equal but opposite force back on object A. “You can’t touch without being touched. You can’t push without being pushed.” Free-Body-Diagrams - FBD’s - what types of forces - where they point, determining Fnet by vector sum of all the forces and Fnet=ma and using that to solve the problem. mass and weight (force of gravity) - how to calculate one from the other, what changes if we go to another planet or moon? What stays the same? Friction - static and kinetic friction- when does static friction break down into kinetic friction. Why does it require less force to keep something moving than start something moving? Inclined plane problems - how to break weight/force of gravity down into parallel perpendicular components, how to set up FBDs and solve on an inclined plane. Multiple Choice Practice Circle the best answer. Justify your answers as requested. Be brief and concise. You may use mathematics to justify. 1. In the absence of a net force, a moving object will 2. A box is pushed toward the right across a (A) slow down and eventually stop classroom floor. The force of friction on the box is (B) stop immediately directed toward the (C) turn right (A) left (D) move with constant velocity (B) right (E) turn left (C) ceiling (D) floor 3. A rocket moves through empty space in a straight 4. A car whose mass is 1500 kg is accelerated line with constant speed. It is far from the uniformly from rest to a speed of 20 m/s in 10 s. The gravitational effect of any star or planet. Under these magnitude of the net force accelerating the car is: conditions, the force that must be (A) 1000 N (B) 2000 N (C) 3000 N applied to the rocket in order to sustain its motion is (D) 20000 N (E) 30000 N A) equal to its weight. B) equal to its mass. C) dependent on how fast it is moving. D) zero. 5. If you push a 4.0-kg mass with the same force that 6. It's more difficult to start moving a heavy carton you push a 10-kg mass from rest, from rest than it is to keep pushing it with A) the 10-kg mass accelerates 2.5 times faster than constant velocity, because the 4.0-kg mass. A) the normal force is greater when the carton is at B) the 4.0-kg mass accelerates 2.5 times faster than rest the 10-kg mass. B) µs < µk C) both masses accelerate at the same rate. C) initially, the normal force is not perpendicular to D) None of the above is true. the applied force D) µk < µs 7. You are standing in a moving bus, facing forward, 8. A brick and a feather fall to the earth at their and you suddenly fall forward as the bus respective terminal velocities. Which object comes to an immediate stop. What force caused you experiences the greater force of air resistance? to fall forward? A) the feather A) gravity B) the brick B) normal force due to your contact with the floor of C) Neither, both experience the same amount of air the bus resistance. C) force due to friction between you and the floor of D) It cannot be determined because there is not the bus enough information given. D) There is not a force leading to your fall. 9. You are standing in a moving bus, facing forward, 10. Action-reaction forces are and you suddenly fall forward as the bus A) equal in magnitude and point in the same direction. comes to an immediate stop. What force caused you B) equal in magnitude but point in opposite directions. to fall forward? C) unequal in magnitude but point in the same A) gravity direction. B) normal force due to your contact with the floor of D) unequal in magnitude and point in opposite the bus directions C) force due to friction between you and the floor of the bus D) There is not a force leading to your fall. 11. A child's toy is suspended from the ceiling by 12. Mass and weight means of a string. The Earth pulls downward A) both measure the same thing. on the toy with its weight force of 8.0 N. If this is the B) are exactly equal. "action force," what is the "reaction C) are two different quantities. force"? D) are both measured in kilograms. A) The string pulling upward on the toy with an 8.0-N force. B) The ceiling pulling upward on the string with an 8.0-N force. C) The string pulling downward on the ceiling with an 8.0-N force. D) The toy pulling upward on the Earth with an 8.0-N force. 13. If the net force on an object were doubled while 14. at the same time the mass of the object was halved, then the acceleration of the object is (A) 1/4 as great. (B) 1/2 as great. (C) 2 times greater. (D) 4 times greater. (E) unchanged  Suppose that an astronaut throws a rock in outer Which one of the following statements is true of an space at a location far from significant object that is at rest? influences of gravity and air resistance. One a. There are no forces acting upon the object. would expect that the rock would ____. b. There is no gravity acting upon the object. a. eventually stop since all objects ultimately c. The individual forces acting upon the object "lose their steam" are balanced. b. continue in motion with the same speed and d. The individual forces acting upon the object direction are NOT balanced. c. eventually stop as its inertia slowly becomes used up d. either a, b, or c -- depending on whether the astronaut continues to push it 9. 10. How much force is required to keep a 4-kg object moving to the right with a constant speed of 8.0 m/s? a. 0 N b. 0.5 N c. 2.0 N d. 32.0 N 12. A skydiver is falling at (constant) terminal velocity before opening her parachute. After opening her parachute, she falls at a much smaller (constant) terminal velocity. How does the total upward force before she opens her parachute compare to the total upward force after she opens her parachute? (A) The ratio of the forces is equal to the ratio of the velocities. (B) The ratio of the forces is equal to the inverse ratio of the velocities. (C) the upward force with the parachute will depend on the size of the parachute. (D) The upward force before the parachute will be greater because of the greater velocity. (E) The upward force in both cases must be the same.  13. A student is looking at the free-body diagram for an object. Which one of the following statements describes how the student can determine if there is a net force? a. If there is an applied force, then there must be a net force. b. If there are less than four forces, then there must be a net force. c. If there is no friction acting upon the object, then there must be a net force. d. If oppositely-directed forces are unequal, then there must be a net force. 14. A leftward moving object is coasting to a stop along a straight, level surface. The net force acting upon the object MUST be ____. a. zero b. directed rightward c. directed leftward d.... impossible to answer without further information. 15. 16. A fish happily swims through the water due to the marvel of Newton's third law. Identify the two letters corresponding to the action-reaction FORCE pairs that are responsible for the fish's motion. List the two letters in alphabetical order with no spaces between letters. a. The fins of the fish push backward on the water. b. The water moves backward and out of the way of the fish. c. The water pressure is greatest behind the fish than in front of it. d. The fish moves forward. e. The water pushes forward upon the fish's fins. f. The muscular and internal pressure of the fish stabilizes its skeletal structure. g. Small bubbles are created as the water swirls and moves backwards. 17. A 0.50-kilogram puck sliding on a horizontal shuffleboard court is slowed to rest by a frictional force of 1.2 newtons. What is the coefficient of kinetic friction between the puck and the surface of the shuffleboard court? 1. 0.24 2. 0.42 3. 0.60 4. 4.1 18. If you exert a force F on an object, the force which the object exerts on you will A) depend on whether or not the object is moving. B) depend on whether or not you are moving. C) depend on the relative masses of you and the object. D) always be F. 19. Fill in the blanks: 20. It's more difficult to start moving a heavy carton from rest than it is to keep pushing it with constant velocity, because A) the normal force is greater when the carton is at rest B) µs < µk C) initially, the normal force is not perpendicular to the applied force D) µk < µs