1. (0 Points) What course is this? a. PHYS 1401 b. PHYS 1402 c. PHYS 2425 d. PHYS 2426 2. (0 Points) Which exam is this? a. Exam 1 b. Exam 2 c. Final Exam 3. (0 Points) What version of the exam is this? a. A b. B c. C d. D 4. Which of these is equivalent to the SI unit of force, the newton? a. kg m/s b. kg m²/s c. kg m²/s² d. kg² m/s² e. kg m/s² 5. Which kinematics quantity is most closely tied to the concept of force? a. Position b. Displacement c. Velocity d. Speed e. Acceleration 6. Which of the following statements is correct? a. If an object currently has no forces acting on it, it cannot possibly be moving. b. If an object currently does have forces acting on it, it cannot possibly be stationary. c. Both (a) and (b) are true. d. Neither (a) nor (b) is true. 7. A bug hits the windshield of a fast-moving car. Which object experiences more force due to the impact? a. The bug. b. The car. c. They experience the same force. 8. Two books are stacked on a desk. Which is the proper description of the normal force acting on the bottom book and caused by the top book? a. Downward and equal to the weight of the top book. b. Upward and equal to the weight of the top book. c. Downward and equal to the combined weight of both books. d. Upward and equal to the combined weight of both books. e. Downward and equal to the weight of the bottom book. 9. If a 5.0 kg mass is hanging at rest from a string, what is the tension in the string? a. 0.0 N b. 0.51 N c. 2.0 N d. 5.0 N e. 49 N 10. If a 5.0 kg mass is hanging from a string, moving upward at a constant 3 m/s, what is the tension in the string? a. 0 N b. 15 N c. 35 N d. 50 N e. 65 N
11. An object is sitting on the flat floor of an elevator. The normal force exerted on the object by the elevator is affected by: a. The vertical velocity component. b. The horizontal velocity component. c. The vertical acceleration component. d. The horizontal acceleration component. e. Both (a) and (c). 12. When an object is on an inclined ramp (0 < θ < 90 ), the magnitude of the normal force is a. 0 b. mg c. mg sin(θ) d. mg cos(θ) e. mg tan(θ) 13. A 3 kg block is sitting at rest on a ramp at an angle of 10. The coefficient of static friction between the block and the ramp is 0.5. What is the magnitude of the friction force acting on the block? a. 2.6 N b. 5.1 N c. 14.5 N d. 14.7 N e. 29.4 N 14. Three 2 kg masses are attached in a horizontal train using small strings. If a 12 N force is pulling the front mass forward, what is the tension force on the back mass? a. 12 N b. 8 N c. 6 N d. 4 N e. 3 N 15. When a car accelerates from rest to 30 m/s, what force propels the car forward? a. The friction force of the car on the road. b. The friction force of the road on the car. c. The normal force of the engine pushing on the car. d. The normal force of the engine pushing on the road. e. Gravity. 16. A block is on a frictionless ramp that is 1.5 m long. Starting from rest, the block is allowed to slide to the bottom of the ramp. What angle of the ramp will allow the block to reach the bottom in 1.1 s? a. 20 b. 15 c. 10 d. 5 e. 0
17. A bicycle traveling at 5 m/s needs to stop in a distance of 3 m. What coefficient of friction is required? a. 8.3 b. 4.2 c. 0.43 d. 0.80 e. 0.85 18. A half-atwood machine is built out of a 10 kg mass on a frictionless horizontal surface. It is attached to a horizontal string that passes over a pulley, and the other end of the string hangs vertically with a 12 kg mass at the bottom. If the system starts from rest, what is the magnitude of its acceleration 0.1 s later? a. 18 m/s² b. 9.8 m/s² c. 8.2 m/s² d. 5.4 m/s² e. 4.5 m/s² 19. An Atwood s Machine is built from m 1 = 1 kg and m 2 = 4 kg. The massless string is passed over a frictionless, massless pulley. When the system is released from rest, what is the tension in the string? a. Less than 9.8 N b. 9.8 N c. Between 9.8 N and 39.2 N d. 39.2 N e. More than 39.2 N 20. Which is a correct equation of motion for a the diagram shown? Assume the motion is in the indicated direction, and the system was released from rest. There is a friction coefficient of μ k between m 2 and the ramp. a. +m 2 g cos(θ) μ k m 2 g sin(θ) + m 1 g = (m 1 + m 2 )a b. +m 2 g sin(θ) + μ k m 2 g cos(θ) m 1 g = (m 1 + m 2 )a c. m 2 g cos(θ) + μ k m 2 g sin(θ) + m 1 g = (m 1 + m 2 )a d. m 2 g sin(θ) μ k m 2 g cos(θ) m 1 g = (m 1 + m 2 )a e. +m 2 g sin(θ) μ k m 2 g cos(θ) m 1 g = (m 1 + m 2 )a 21. The density of ice is 917 kg/m³. The density of seawater is about 1030 kg/m³. What percentage of the volume of a floating iceberg is sticking up above the surface of the water? a. 89% b. 50% c. 12% d. 11% e. 0%
22. A magnesium block has a weight of 34.8 N. When the block is suspended under water by a string, the tension in the string is 14.8 N. What is the density of magnesium? a. 1350 kg/m³ b. 1740 kg/m³ c. 2350 kg/m³ d. 3350 kg/m³ e. 3480 kg/m³ 23. A heavy ball is held up by two strings. One is horizontal while the other is tilted at an angle of 60 from the horizontal. The tension in the diagonal string (T 1 in the diagram) is 50 N. What is the weight of the ball? a. 25 N b. 29 N c. 43 N d. 50 N e. 87 N 24. An ideal meter stick is balanced on a pencil which is at the 30 cm mark. A 150 g mass sits at the 20 cm mark. What is the mass of the meter stick? a. 50 g b. 75 g c. 90 g d. 150 g e. 300 g 25. The free body diagram below represents a 1500 kg car sitting on a 3000 kg bridge supported at its far ends. The car's position is three quarters of the length L from the left end of the bridge. Identify the one error in the torque equation: F 1 L F g (L/2) F car (3L/4) + F 2 L = 0 (Hint: figure out where the pivot point should be so that there is only one error in the equation.) a. F 1 L should be negative. b. F 1 L should be 0. c. F 2 L should be 0. d. F car (3L/4) should be F car (L/4) e. There is no error.
26. A student has drawn a free-body diagram for a ladder of mass m leaning against a frictionless wall. The diagram is shown below. What is the error in the diagram? a. f s is in the wrong direction. b. F wall should be directed upwards, not down. c. F wall should be perpendicular to the wall, not parallel to it. d. n should be down into the floor for f s to have the given direction. e. F wall should be diagonal or split into components. 27. A diagonal bar is pinned at the origin and extends up to (6 m)i + (8 m)j. Its weight is 10 N. How much torque about the pin does the gravitational force of Earth cause? (As usual, j is the vectical direction.) a. 10 N m b. 30 N m c. 40 N m d. 60 N m e. 100 N m 28. A uniform beam having a mass of 60 kg and a length of 2.8 m is held in place at its lower end by a pin. Its upper end leans against a vertical frictionless wall as shown in the figure. What is the magnitude of the force the pin exerts on the beam? a. 0.68 kn b. 0.57 kn c. 0.74 kn d. 0.63 kn e. 0.35 kn