Page 1. Name: 1) The diagram below represents two concurrent forces.

Transcription

1 Name: Page 1 1) The diagram below represents two concurrent forces. Which vector represents the force that will produce equilibrium with these two forces? 2) Which diagram represents a box in equilibrium? 3) An 80-kilogram skier slides on waxed skis along a horizontal surface of snow at constant velocity while pushing with his poles. What is the horizontal component of the force pushing him forward? 0.05 N 40 N 0.4 N 4 N 4) In the diagram below, a 20.-newton force due north and a 20.-newton force due east act concurrently on an object, as shown in the diagram below. What additional force is necessary to bring the object into a state of equilibrium? 20. N, northeast 28 N, northeast 28 N, southwest 20. N, southwest 5) As the angle between two concurrent forces decreases, the magnitude of the force required to produce equilibrium increases decreases remains the same

2 Questions 6 and 7 refer to the following: Page 2 A stream is 30. meters wide and its current flows southward at 1.5 meters per second. A toy boat is launched with a velocity of 2.0 meters per second eastward from the west bank of the stream. 6) Based on the given information, what is the magnitude of the toy boat's resultant velocity as it crosses the stream? 3.5 m/s 0.5 m/s 3.0 m/s 2.5 m/s 7) Based on the given information, how much time is required for the toy boat to reach the opposite bank of the stream? 8.6 s 12 s 60. s 15 s 8) In the diagram below, scaled vectors represent the momentum of each of two masses, A and B, sliding toward each other on a frictionless, horizontal surface. Which of the following scaled vectors best represents the momentum of the system after the masses collide? 9) A block weighing 10.0 newtons is on a ramp inclined at 30.0D to the horizontal. A 3.0-newton force of friction, F f, acts on the block as it is pulled up the ramp at constant velocity with force F, which is parallel to the ramp, as shown in the diagram below. What is the magnitude of force F? 8.0 N 10. N 7.0 N 13 N 10) An airplane flies with a velocity of 750. kilometers per hour, 30.0D south of east. What is the magnitude of the eastward component of the plane's velocity? 433 km/h 866 km/h 375 km/h 650. km/h 11) A 6.0-newton force and an 8.0-newton force act concurrently on a point. As the angle between these forces increases from 0D to 90D, the magnitude of their resultant decreases increases remains the same 12) A bicycle and its rider have a combined mass of 80. kilograms and a speed of 6.0 meters per second. What is the magnitude of the average force needed to bring the bicycle and its rider to a stop in 4.0 seconds? 3.2 x 10 2 N 1.2 x 10 2 N 1.9 x 10 3 N 4.8 x 10 2 N 13) A force of one newton is equivalent to one

3 14) A soccer player kicks a ball with an initial velocity of 10. meters per second at an angle of 30.D above the horizontal. What is the magnitude of the horizontal component of the ball's initial velocity? 9.8 m/s 5.0 m/s 8.7 m/s 10. m/s 15) What is the magnitude of the force needed to keep a 60.-newton rubber block moving across level, dry asphalt in a straight line at a constant speed of 2.0 meters per second? 40. N 51 N 120 N 60. N 16) Which vector diagram best represents a cart slowing down as it travels to the right on a horizontal surface? Page 3 17) Two students push on a sled. One pushes with a force of 30. newtons east and the other exerts a force of 40. newtons south, as shown in the top-view diagram below. Which vector best represents the resultant of these two forces? 18) The diagram below represents a force vector, A, and a resultant vector, R. Which force vector B below could be added to force vector A to produce resultant vector R?

4 19) A force vector was resolved into two perpendicular components, F l and F 2, as shown in the diagram below Page 4 Which vector best represents the original force? 20) A 5.0-newton force and a 7.0-newton force act concurrently on a point. As the angle between the forces is increased from 0D to 180D, the magnitude of the resultant of the two forces changes from 2.0 N to 12.0 N 12.0 N to 2.0 N 0.0 N to 12.0 N 12.0 N to 0.0 N 21) The diagram below shows a resultant vector, R. Which diagram best represents a pair of component vectors, A and B, that would combine to form resultant vector R? 22) If the sum of all the forces acting on a moving object is zero, the object will continue moving with constant velocity change the direction of its motion accelerate uniformly slow down and stop 23) Two students are pushing a car. What should be the angle of each student's arms with respect to the flat ground to maximize the horizontal component of the force? 90D 45D 0D 30D 24) Two concurrent forces have a maximum resultant of 45 newtons and a minimum resultant of 5 newtons. What is the magnitude of each of these forces? 5 N and 9 N 0 N and 45 N 0 N and 50. N 20. N and 25 N

5 25) The diagram below represents a 5.0 newton force and a 12-newton force acting on point P Page 5 The resultant of the two forces has a magnitude of 12 N 13 N 5.0 N 7.0 N 26) The vector diagram below represents two forces, F 1 and F 2, simultaneously acting on an object. Which vector best represents the resultant of the two forces? 27) A 2.0-kilogram laboratory cart is sliding across a horizontal frictionless surface at a constant velocity of 4.0 meters per second east. What will be the cart's velocity after a 6.0-newton westward force acts on it for 2.0 seconds? 10. m/s east 2.0 m/s west 10. m/s west 2.0 m/s east 28) The diagram below shows a block on a horizontal frictionless surface. A 100.-newton force acts on the block at an angle of 30.D above the horizontal. What is the magnitude of force F if it establishes equilibrium? 86.6 N 50.0 N 100. N 187 N 29) Which two graphs represent the motion of an object on which the net force is zero?

6 30) In which situation is the net force on the object equal to zero? a pitched baseball being hit by a bat an automobile braking to a stop a bicycle moving at constant speed on a straight, level road a satellite moving at constant speed around Earth in a circular orbit 31) The diagram below represents two forces acting concurrently on an object at point P Page 6 Which diagram best represents the resultant of these two forces? 32) A 5-newton force directed east and a 5-newton force directed north act concurrently on a point. What is the resultant of the two forces? 5 N northeast 7 N northeast 10. N southwest 7 N southwest 33) A 3-newton force and a 4-newton force are acting concurrently on a point. Which force could not produce equilibrium with these two forces? 4 N 1 N 7 N 9 N 34) A 5.0-newton force could have perpendicular components of 3.0 N and 4.0 N 1.0 N and 4.0 N 2.0 N and 3.0 N 5.0 N and 5.0 N 35) Forces A and B have a resultant R. Force A and resultant R are represented in the diagram below. Which vector best represents force B? 36) What is an essential characteristic of an object in equilibrium? zero velocity zero kinetic energy zero potential energy zero acceleration 37) Which graph best represents the motion of an object that is not in equilibrium as it travels along a straight line?

7 38) Into how many possible components can a single force be resolved? three components four components at right angles to each other an unlimited number two components 39) Which pair of forces acting concurrently on an object will produce the resultant of greatest magnitude? Page 7 40) The diagram below shows a 1.0-newton metal disk resting on an index card that is balanced on top of a glass. What is the net force acting on the disk shown in the diagram? 1.0 N 2.0 N 0 N 9.8 N 41) Two 30.-newton forces act concurrently on an object. In which diagram would the forces produce a resultant with a magnitude of 30. newtons?