Assessment Chapter Test A Teacher Notes and Answers Forces and the Laws of Motion CHAPTER TEST A (GENERAL) 1. c 2. d 3. d 4. c 5. c 6. c 7. c 8. b 9. d 10. d 11. c 12. a 13. d 14. d 15. b 16. d 17. c 18. d 19. Forces exerted by the object do not change its motion. 20. An object at rest remains at rest and an object in motion continues in motion with constant velocity unless it experiences a net external force. 21. F is the vector sum of the external forces acting on the object. 22. In most cases, air resistance increases with increasing speed. 23. 27 N, to the right F1 = 102 N, to the right F = 75 N, to the left 2 F net = F 1 + F 2 F net = F 1 F 2 = 102 N 75 N = 27 N F net = 27 N, to the right 24. 16 N m = 33 kg a = 0.50 m/s 2 F net,x = F x = ma x = (32 kg)(0.50 m/s 2 ) = 16 N 25. 10.4 N m = 1.10 kg = 15.0 g = 9.81 m/s 2 F net, y = F y = F n F y = 0 = 180 90 15.0 =75.0 F n = F y = F g sin = mg sin F n = (1.10 kg)(9.81 m/s 2 )(sin 75.0 ) = 10.4 N Holt Physics 1 Chapter Tests
Assessment Forces and the Laws of Motion Chapter Test A MULTIPLE CHOICE In the space provided, write the letter of the term or phrase that best completes each statement or best answers each question. 1. Which of the following is the cause of an acceleration? a. speed c. force b. inertia d. velocity 2. What causes a moving object to change direction? a. acceleration c. inertia b. velocity d. force 3. Which of the following forces exists between objects even in the absence of direct physical contact? a. frictional force c. contact force b. fundamental force d. field force 4. A newton is equivalent to which of the following quantities? a. kg c. kg m/s 2 b. kg m/s d. kg (m/s) 2 5. The length of a force vector represents the a. cause of the force. b. direction of the force. c. magnitude of the force. d. type of force. 6. A free-body diagram represents all of the following except a. the object. b. forces as vectors. c. forces exerted by the object. d. forces exerted on the object. 7. In the free-body diagram shown to the right, which of the following is the gravitational force acting on the car? a. 5800 N c. 14 700 N b. 775 N d. 13 690 N Holt Physics 2 Chapter Tests
8. Which of the following is the tendency of an object to maintain its state of motion? a. acceleration c. force b. inertia d. velocity 9. A crate is released on a frictionless plank inclined at angle with respect to the horizontal. Which of the following relationships is true? (Assume that the x-axis is parallel to the surface of the incline.) a. F y = F g c. F y = F x b. F x = 0 d. none of the above 10. A car goes forward along a level road at constant velocity. The additional force needed to bring the car into equilibrium is a. greater than the normal force times the coefficient of static friction. b. equal to the normal force times the coefficient of static friction. c. the normal force times the coefficient of kinetic friction. d. zero. 11. If a nonzero net force is acting on an object, then the object is definitely a. at rest. c. being accelerated. b. moving with a constant velocity. d. losing mass. 12. Which statement about the acceleration of an object is correct? a. The acceleration of an object is directly proportional to the net external force acting on the object and inversely proportional to the b. The acceleration of an object is directly proportional to the net external force acting on the object and directly proportional to the c. The acceleration of an object is inversely proportional to the net external force acting on the object and inversely proportional to the d. The acceleration of an object is inversely proportional to the net external force acting on the object and directly proportional to the 13. Which are simultaneous equal but opposite forces resulting from the interaction of two objects? a. net external forces c. gravitational forces b. field forces d. action-reaction pairs 14. Newton s third law of motion involves the interactions of a. one object and one force. c. two objects and one force. b. one object and two forces. d. two objects and two forces. Holt Physics 3 Chapter Tests
15. The magnitude of the gravitational force acting on an object is a. frictional force. c. inertia. b. weight. d. mass. 16. A measure of the quantity of matter is a. density. c. force. b. weight. d. mass. 17. A change in the gravitational force acting on an object will affect the object s a. mass. c. weight. b. coefficient of static friction. d. inertia. 18. What are the units of the coefficient of friction? a. N c. N 2 b. 1/N d. The coefficient of friction has no units. SHORT ANSWER 19. In a free-body diagram of an object, why are forces exerted by the object not included in the diagram? 20. State Newton s first law of motion. 21. In the equation form of Newton s second law, F = ma, what does F represent? 22. What happens to air resistance when an object accelerates? Holt Physics 4 Chapter Tests
PROBLEM 23. In a game of tug-of-war, a rope is pulled by a force of 75 N to the left and by a force of 102 N to the right. What is the magnitude and direction of the net horizontal force on the rope? 24. A wagon having a mass of 32 kg is accelerated across a level road at 0.50 m/s 2. What net force acts on the wagon horizontally? 25. Basking in the sun, a 1.10 kg lizard lies on a flat rock tilted at an angle of 15.0 with respect to the horizontal. What is the magnitude of the normal force exerted by the rock on the lizard? Holt Physics 5 Chapter Tests