Phys 2425: University Physics I Summer 2016 Practice Exam 1

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1 1. (0 Points) What course is this? a. PHYS 1401 b. PHYS 1402 c. PHYS 2425 d. PHYS (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. What are the units of the imaginary quantity slurm, which is equal to acceleration divided by velocity squared? a. m 2 /s 3 b. 1 c. s/m d. s e. 1/m 5. Express the following quantity using an SI prefix: m a. 230 nm b. 2.3 μm c. 23 μm d. 230 μm e. 23 mm 6. In Newtonian Mechanics (which is what we study), under what conditions is the equation x = x 0 + v avg Δt valid to use? a. Stationary object only. b. Constant velocity only. c. Constant acceleration only. d. Only when the acceleration is varying. e. It is generally true. 7. Which diagram could represent the position of a car accelerating from rest? 8. One student throws a heavy red ball horizontally from a balcony of a tall building with an initial speed v i. At the same time, a second student drops a lighter blue ball from the balcony. Neglecting air resistance, which statement is true? a. The blue ball reaches the ground first. b. The balls reach the ground at the same instant. c. The red ball reaches the ground first. d. Both balls hit the ground with the same speed. e. None of statements (a) through (d) is true. 9. A person drives from home to work at a constant speed of 15 m/s. On the way home, they drive 30 m/s. What is the average speed of their driving? a m/s b. 20 m/s c m/s d. 25 m/s e m/s

2 (Questions 10 12) An object moves according to the equation Δx = 8t + 3t 2 t What is the magnitude of its acceleration at time t = 0? m/s² b. 1 m/s² c. 2 m/s² d. 3 m/s² e. 6 m/s² 11. What its speed at time t = 0? a. 2 m/s b. 3 m/s c. 7 m/s d. 8 m/s e. 13 m/s 12. What is it doing at time t = 0? a. Temporarily not moving. b. Moving at constant velocity. c. Moving and speeding up. d. Moving and slowing down. e. Moving and changing direction. 13. A car travelling at a highway speed of 30 m/s slows to a stop in 150 m. What is its average speed during the process? m/s c. 15 m/s d. 30 m/s e. 60 m/s 14. If you drop a ball from a height of 0.5 m, how much time does it take for it to hit the ground?.05 s b s c s d s e. 6.6 s 15. A plane is flying in a direction described by an azimuth of 170. The definition of azimuth is the angle clockwise from north or east of north. What mathematical polar coordinate angle corresponds to this azimuth? a. 80 b. 10 c. 10 d. 80 e If a 6 ft. tall vertical pole casts a shadow that is 2 ft. long, what is the angle of the sun above the horizon? a. 18 b. 19 c. 30 d. 60 e. 72

3 17. A golfer can hit a ball with an initial speed of 80 m/s. Assuming projectile motion, what is the maximum range the ball could go? a. 8 m b. 80 m c. 160 m d. 327 m e. 653 m (Questions 18 22) A ball is fired from a launcher with an initial speed of 12 m/s at an angle of 60 above the horizontal. It is fired from ground level up onto the roof of a building, which is 4 m above the ground. 18. The x-component of the ball s initial velocity is: c. 6 m/s d m/s e. 12 m/s 19. The y-component of the ball s initial velocity is: c. 6 m/s d m/s e. 12 m/s 20. At the point of landing, the y-component of the ball s velocity is: b. 2.6 m/s c. 4.5 m/s d. 5.4 m/s e. 6.3 m/s 21. The amount of time the ball in the air is:.5 s b. 0.8 s c. 1.6 s d. 2.4 s e. 3.6 s 22. The range (horizontal distance) of the ball s flight is: a. 4.0 m b. 5.6 m c. 8.4 m d. 9.7 m e m 23. A ball is tossed straight up into the air. When is its acceleration pointing in the same direction as its velocity? a. On the way up. b. At the top. c. On the way down. d. Both (a) and (b). e. All of the above.

4 24. A particular car can stop from 30 m/s on dry road in a distance of 54 m. Assuming the same driving conditions, what is the car s stopping distance from 10 m/s? a. 5.1 m b. 6.0 m c. 9.0 m d. 18 m e. 31 m 25. For a horizontally-launched projectile, which is the correct formula for the distance fallen (h) depending on the horizontal range (x)? a. h = 1 2 gx/v 0 b. h = 1 2 gx2 /v 0 2 c. h = 1 2 gx/v 0 2 d. h = 1 2 gv 0 2 /x Two forces are known to be F 1 = 6.0 N in the x-direction, and F 2 = 8.0 N at an angle of 130. What is the direction of a the resultant F 1 + F 2? a. 48 b. 75 c. 82 d. 113 e A car is driving at a steady speed of 30 m/s, and at the moment they drive by, a motorcycle starts to chase it. The motorcycle starts from rest and accelerates at a rate of 5 m/s² until it catches up with the car. How far does the car get before the motorcycle catches up? a. 6 m b. 180 m c. 360 m d. 720 m e. It never catches up. 28. A basketball player is 10.0 m from the basket, which is 1.0 m above the ball. If the player shoots the ball at an angle of 45 above the horizontal, what speed must be used so that the ball goes in the basket? a. 5 m/s b. 10 m/s c. 15 m/s d. 20 m/s e. 25 m/s

5 29. If an object is thrown straight downward with a speed v 0 from the top of a building of height h, which is the correct equation for the position as a function of time? Take y = 0 to be ground level. a. y = h v 0 t 1 2 gt2 b. y = h + v 0 t gt2 c. y = v 0 gt d. y = h v 0 t gt2 e. y = h + v 0 t 1 2 gt2 30. A velocity vector has a y-component v y = 3.0 m/s and it is at an angle of 37 CCW from the x-axis. What is its magnitude? a. 1.8 m/s b. 2.4 m/s c. 3.7 m/s d. 5 m/s e. 6 m/s (Questions 31 32) To drive from home to the store, somebody first travels at 20 m/s south for 120 s, and then they travel 20 m/s at an angle of 60 north of east for 120 s. 31. What is the magnitude of their average velocity for the trip? b. 5.2 m/s c m/s d m/s e. 20 m/s 32. What is their average speed for the trip? b. 5.2 m/s c m/s d m/s e. 20 m/s