5. The graph represents the net force acting on an object as a function of time. During which time interval is the velocity of the object constant?

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1 1. A 0.50-kilogram cart is rolling at a speed of 0.40 meter per second. If the speed of the cart is doubled, the inertia of the cart is A) halved B) doubled C) quadrupled D) unchanged 2. A force of 25 newtons east and a force of 25 newtons west act concurrently on a 5.0-kilogram cart. What is the acceleration of the cart? A) 1.0 m/s 2 west B) 5.0 m/s 2 east C) 0.20 m/s 2 east D) 0 m/s 2 3. A person is standing on a bathroom scale in an elevator car. If the scale reads a value greater than the weight of the person at rest, the elevator car could be moving A) downward at constant speed B) upward at constant speed C) downward at increasing speed D) upward at increasing speed 4. Base your answer to the following question on Two forces are applied to a 2.0-kilogram block on a frictionless horizontal surface, as shown in the diagram below. 5. The graph represents the net force acting on an object as a function of time. During which time interval is the velocity of the object constant? A) 0 to 2 B) 2 to 3 C) 3 to 4 D) 4 to 5 6. Base your answer to the following question on Two forces, F1 and F2, are applied to a block on a frictionless, horizontal surface as shown below. The acceleration of the block is A) 1.5 m/s 2 to the right B) 2.5 m/s 2 to the left C) 2.5 m/s 2 to the right D) 4.0 m/s 2 to the left If the magnitude of the block's acceleration is 2.0 meters per second 2, what is the mass of the block? A) 1 kg B) 5 kg C) 6 kg D) 7 kg 7. What is the magnitude of the net force acting on a kilogram car as it accelerates from rest to a speed of 15 meters per second in 5.0 seconds? A) N B) N C) N D) N 8. Earth s mass is approximately 81 times the mass of the Moon. If Earth exerts a gravitational force of magnitude F on the Moon, the magnitude of the gravitational force of the Moon on Earth is A) F B) F 81 C) 9F D) 81F

2 9. Two equal point masses are separated by a distance of 1 meter. If one mass is doubled, the gravitational force between the two masses would be A) one-half as great B) two times greater C) one-fourth as great D) four times greater 10. Which graph best represents the relationship between the mass (m) of a satellite launched from Earth and the satellite's distance (r) away from Earth? A) B) 14. Base your answer to the following question on A book weighing 20. Newtons slides at constant velocity down a ramp inclined 30.º to the horizontal as shown in the diagram below. C) D) 11. As the distance between two objects increases, the gravitational force of attraction between them will A) decrease B) increase C) remain the same 12. A 60.-kilogram physics student would weigh 1560 newtons on the surface of planet X. What is the magnitude of the acceleration due to gravity on the surface of planet X? A) m/s 2 B) 6.1 m/s 2 C) 9.8 m/s 2 D) 26 m/s Base your answer to the following question on The graph below shows the weight of three objects on planet X as a function of their mass. What is the force of friction between the book and the ramp? A) 10. N up the ramp B) 17 N up the ramp C) 10. N down the ramp D) 17 N down the ramp 15. In order to keep an object weighing 20 Newtons moving at constant speed along a horizontal surface, a force of 10 Newtons is required. The force of friction between the surface and the object is A) 0 N B) 10 N C) 20 N D) 30 N 16. 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? A) 0.24 B) 0.42 C) 0.60 D) 4.1 The acceleration due to gravity on planet X is A) 0.17 m/s 2 B) 6.0 m/s 2 C) 9.8 m/s 2 D) 50. m/s 2

3 17. Base your answer to the following question on The diagram below represents two concurrent forces. Which vector represents the force that will produce equilibrium with these two forces? A) B) C) D) 18. Base your answer to the following question on The vector diagram below represents two forces, F1 and F2 simultaneously acting on an object. Which vector best represents the resultant of the two forces? A) B) C) D)

4 19. Base your answer to the following question on The diagram below shows a block on a horizontal frictionless surface. A newton force acts on the block at an angle of 30. above the horizontal. What is the magnitude of force F if it establishes equilibrium? A) 50.0 N B) 86.6 N C) 100. N D) 187 N 20. Base your answer to the following question on the information below. A student and the waxed skis he is wearing have a combined weight of 850 newtons. The skier travels down a snow-covered hill and then glides to the east across a snow-covered, horizontal surface. Calculate the magnitude of the force of friction acting on the skis as the skier glides across the snow-covered, horizontal surface. [Show all work, including the equation and substitution with units.]

5 Answer Key Forces Readiness 1. D 2. D 3. D 4. B 5. C 6. B 7. A 8. A 9. B 10. A 11. A 12. D 13. B 14. A 15. B 16. A 17. C 18. B 19. B 20. Ff = µfn ; Ff = (0.05)(850 N);