Forces Review. A. less than the magnitude of the rock s weight, but greater than zero A. 0 B. 45 C. 90. D. 180.

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1 Name: ate: 1. Two 20.-newton forces act concurrently on an object. What angle between these forces will produce a resultant force with the greatest magnitude?. 0 B. 45 C rock is thrown straight up into the air. t the highest point of the rock s path, the magnitude of the net force acting on the rock is. less than the magnitude of the rock s weight, but greater than zero B. greater than the magnitude of the rock s weight 2. Which object has the greatest inertia? C. the same as the magnitude of the rock s weight. zero. a kg bullet traveling at 90. m/s B. a 30.-kg child traveling at 10. m/s on her bike C. a 490-kg elephant walking with a speed of 1.0 m/s. a 1500-kg car at rest in a parking lot 3. n 8.0-newton wooden block slides across a horizontal wooden floor at constant velocity. What is the magnitude of the force of kinetic friction between the block and the floor? 6. The diagram below shows a compressed spring between two carts initially at rest on a horizontal, frictionless surface. Cart has a mass of 2 kilograms and cart B has a mass of 1 kilogram. string holds the carts together N B. 3.4 N C. 8.0 N. 27 N 4. Which situation represents a person in equilibrium?. a child gaining speed while sliding down a slide B. a woman accelerating upward in an elevator The string is cut and the carts move apart. Compared to the magnitude of the force the spring exerts on cart, the magnitude of the force the spring exerts on cart B is. the same B. half as great C. twice as great. four times as great C. a man standing still on a bathroom scale. a teenager driving around a corner in his car page 1

2 7. n 8.0-newton block is accelerating down a frictionless ramp inclined at 15 to the horizontal, as shown in the diagram below. 10. Four forces act concurrently on a block on a horizontal surface as shown in the diagram below. What is the magnitude of the net force causing the block s acceleration?. 0 N B. 2.1 N C. 7.7 N. 8.0 N s a result of these forces, the block. moves at constant speed to the right B. moves at constant speed to the left 8. t a certain location, a gravitational force with a magnitude of 350 newtons acts on a 70.-kilogram astronaut. What is the magnitude of the gravitational field strength at this location? C. accelerates to the right. accelerates to the left kg/n B. 5.0 N/kg C. 9.8 m/s N kg 9. dry plastic rod is rubbed with wool cloth and then held near a thin stream of water from a faucet. The path of the stream of water is changed, as represented in the diagram below. 11. Base your answer(s) to the following question(s) on the information and diagram below newton force is used to slide a 40.0-newton crate a distance of 6.00 meters at constant speed along an incline to a vertical height of 3.00 meters. etermine the total work done by the 30.4-newton force in sliding the crate along the incline. Which force causes the path of the stream of water to change due to the plastic rod?. nuclear B. magnetic C. electrostatic. gravitational 12. Calculate the total increase in the gravitational potential energy of the crate after it has slid 6.00 meters along the incline. page 2

3 13. State what happens to the kinetic energy of the crate as it slides along the incline. 18. number of 1.0-newton horizontal forces are exerted on a block on a frictionless, horizontal surface. Which top-view diagram shows the forces producing the greatest magnitude of acceleration of the block? 14. State what happens to the internal energy of the crate as it slides along the incline.. B. 15. Which object has the greatest inertia?. a 15-kg mass traveling at 5.0 m/s B. a 10.-kg mass traveling at 10 m/s C. a 10.-kg mass traveling at 5.0 m/s C.. a 5.0-kg mass traveling at 15 m/s 16. n unbalanced force of 40. newtons keeps a 5.0-kilogram object traveling in a circle of radius 2.0 meters. What is the speed of the object? m/s B. 2.0 m/s C. 16 m/s. 4.0 m/s 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? B C On a small planet, an astronaut uses a vertical force of 175 newtons to lift an 87.5-kilogram boulder at constant velocity to a height of meter above the planet s surface. What is the magnitude of the gravitational field strength on the surface of the planet? N/kg B N/kg C N/kg N/kg page 3

4 20. The length of a football field is closest to cm B dm C km mm 21. Which graph represents the relationship between the magnitude of the gravitational force exerted by Earth on a spacecraft and the distance between the center of the spacecraft and center of Earth? [ssume constant mass for the spacecraft.] 22. Base your answer(s) to the following question(s) on the information below. 28-gram rubber stopper is attached to a string and whirled clockwise in a horizontal circle with a radius of 0.80 meter. The diagram in your answer booklet represents the motion of the rubber stopper. The stopper maintains a constant speed of 2.5 meters per second. On the diagram below, draw an arrow showing the direction of the centripetal force acting on the stopper when it is at the position shown.. B. C Calculate the magnitude of the centripetal acceleration of the stopper. page 4

5 24. stone on the end of a string is whirled clockwise at constant speed in a horizontal circle as shown in the diagram below. Which pair of arrows best represents the directions of the stone s velocity, v, and acceleration, a, at the position shown?. B. C.. page 5

6 kilogram boy and a 50.0-kilogram girl, each holding a spring scale, pull against each other as shown in the diagram below. The graph below shows the relationship between the magnitude of the force that the boy applies on his spring scale and time. Which graph best represents the relationship between the magnitude of the force that the girl applies on her spring scale and time?. B. C.. page 6

7 26. Base your answer(s) to the following question(s) on the information below. student produced various elongations of a spring by applying a series of forces to the spring. The graph below represents the relationship between the applied force and the elongation of the spring. 29. The magnitude of the centripetal force acting on an object traveling in a horizontal, circular path will decrease if the. radius of the path is increased B. mass of the object is increased C. direction of motion of the object is reversed. speed of the object is increased 30. The centripetal force acting on the space shuttle as it orbits Earth is equal to the shuttle s. inertia B. momentum C. velocity. weight etermine the spring constant of the spring. 27. Calculate the magnitude of the average gravitational force between Earth and the Moon. [Show all work, including the equation and substitution with units.] 31. Two forces act concurrently on an object on a horizontal, frictionless surface, as shown in the diagram below. 28. student is standing in an elevator that is accelerating downward. The force that the student exerts on the floor of the elevator must be What additional force, when applied to the object, will establish equilibrium?. less than the weight of the student when at rest B. greater than the weight of the student when at rest C. less than the force of the floor on the student. 16 N toward the right B. 16 N toward the left C. 4 N toward the right. 4 N toward the left. greater than the force of the floor on the student page 7

8 32. s shown in the diagram below, an open box and its contents have a combined mass of 5.0 kilograms. horizontal force of 15 newtons is required to push the box at a constant speed of 1.5 meters per second across a level surface. 34. 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.] The inertia of the box and its contents increases if there is an increase in the 35. child pulls a wagon at a constant velocity along a level sidewalk. The child does this by applying a 22-newton force to the wagon handle, which is inclined at 35 to the sidewalk as shown below.. speed of the box B. mass of the contents of the box C. magnitude of the horizontal force applied to the box. coefficient of kinetic friction between the box and the level surface What is the magnitude of the force of friction on the wagon?. 11 N B. 13 N C. 18 N. 22 N 33. Base your answer(s) to the following question(s) on the information below. 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. etermine the magnitude of the normal force exerted by the snow on the skis as the skier glides across the horizontal surface. 36. Base your answer(s) to the following question(s) on the information below. vertically hung spring has a spring constant of 150. newtons per meter kilogram mass is suspended from the spring and allowed to come to rest. Calculate the elongation of the spring produced by the suspended 2.00-kilogram mass. [Show all work, including the equation and substitution with units.] page 8

9 Problem-ttic format version c Educide Software Licensed for use by avid Sands Terms of Use at 06/03/ C C B B C 128 J PE = 120. J The kinetic energy of the crate is constant. The internal energy of the crate increases. B B a c = 7.8 m/s N/m 27. F g = Gm 1m 2 r 2 ; F g = N B 850 N

10 Teacher s Key Page F f = µf N, F f = (0.05)(850 N), F f = 40 N C x = F s k = mg k, x = m