Indicate Whether the Sentence Or Statement Is True Or False. s1

Physics 11 Final Exam Review – January 2010 Name:

True/False (Indicate whether the sentence or statement is true or false.)

1. The slope of a position-time graph represents the velocity. 2. An object dropped from a window falls to the ground. The position-time graph representing the object's motion would be a straight line. 3. A car accelerates uniformly when the traffic light turns green. The velocity-time graph representing the car's motion would be a straight line. 4. The slope of the tangent to a point on a curve that is part of a position-time graph represents the instantaneous velocity. 5. Consider a trip from your home to your school and back home again. The magnitude of your displacement is equivalent to your distance travelled. 6. The reason your head feels like it jerks backward when pulling away from a stop sign is best explained by Newton's First Law. 7. If the vector sum of all forces acting on an object is precisely zero, the object could still be moving. 8. An elevator moves vertically upward with a constant speed. The vector sum of all the forces acting on the elevator is precisely zero. 9. For any pair of surfaces, the coefficient of static friction between the surfaces is less than the corresponding coefficient of sliding friction. 10. Work is done when a net force is applied to an object over a certain distance. 11. Negative work means the force applied is opposite to the direction of the displacement. 12. Power is the rate of doing work. 13. In a transverse wave, the particles in the medium move in a direction perpendicular to the direction of the wave. 14. In a longitudinal wave, the particles in the medium move in a direction perpendicular to the direction of the wave. 15. The universal wave equation can be used to directly calculate the amplitude of a wave. 16. Destructive interference in a longitudinal wave occurs when two compressions meet, or act simultaneously on the same particles of a medium.

Multiple Choice (Identify the letter of the choice that best completes the statement or answers the question.)

1. Which of the following is a "scalar" quantity? a. distance d. displacement b. velocity e. none of the above c. acceleration

2. The term "uniform motion" means a. acceleration is constant d. displacement is constant b. speed is constant e. velocity is zero c. velocity is constant 3. An 80.4-km trip takes a time of 0.75 h to complete. The average speed (with correct sig figs) is a. 107.2 km/h d. 1 x 102 km/h b. 1.072 x 102 km/h e. 1.1 x 102 km/h c. 29.8 m/s

4. Use the position-time graph pictured below and select the statement that is true.

a. The object accelerates, stops, then accelerates in the opposite direction. b. The object's speed is greatest during the first segment. c. The object's acceleration is greatest during the last segment. d. The object's average velocity is zero. e. The object travels a greater distance in the first segment than in the last segment.

5. Over a period of 3.0 seconds a car's velocity changes from 18 m/s [W] to 12 m/s [W]. What is the value of the car's acceleration during this time? a. 2.0 m/s2 [E] d. 10 m/s2 [E] b. 10 m/s2 [W] e. 2.0 m/s [E] c. 2.0 m/s2 [W]

6. If an object accelerates at 6.2 m/s2 [N], how long will it take to reach a velocity of 25 m/s [N] if starting from rest? a. 25 s d. 0.25 s b. 4.0 m/s e. 4.0 s c. 31 s

7. An object is thrown vertically upward at 25.0 m/s. If it experiences acceleration due to gravity of 9.8 m/s2 [down], what is the object's velocity 3.0 s later? a. 22 m/s [down] d. 4 m/s [down] b. 22 m/s [up] e. zero (it has hit the ground) c. 4 m/s [up]

8. A stone is thrown vertically downward with a speed of 10 m/s from a bridge. Accelerating under gravity (9.8 m/s2), the stone strikes the water 1.8 s later. From what height above the water was the stone thrown? (Assume 2 significant digits.) a. 50 m d. 15 m b. 34 m e. 3 m c. 27 m

9. An elevator is suspended by a cable and moves upward. Which of the following free-body diagrams best represents the forces acting on the elevator? a. A d. D b. B e. E c. C

10. A heavy crate is pushed across a rough surface. The force that is ultimately responsible for the crate's motion is the a. applied force d. net force b. frictional force e. normal force c. gravitational force

11. A hockey puck of mass 150 g is sliding south along the ice and slows at a rate of 1.2 m/s2. What is the net force acting on the puck? a. 1.8 x 102 N [N] d. 1.8 x 10-1 N [N] b. 1.8 x 102 N [S] e. 1.9 x 10-1 N [S] c. 1.8 x 101 N [N]

12. Newton's third law essentially states a. objects won't move unless pushed b. acceleration only occurs if there is net force c. the acceleration of an object depends on its mass and the net force acting on it d. objects which are moving tend to stay moving e. forces always occur in pairs

13. If you weighed 112 N on the Moon where g = 1.6 N/kg, how much would you weigh on Earth? a. 1.1 x 102 N d. 1.1 x 104 N b. 1.7 x 104 N e. 6.9 x 103 N c. 6.9 x102 N

14. The value of "g" at the surface of Mars is 3.7 N/kg. How much would a 60.0-kg person weigh at an altitude above the Martian surface equivalent to the planet's radius? a. 2.2 x 102 N d. 56 N b. 1.6 x 102 N e. 28 N c. 1.1 x 102 N

15. The force of friction always acts in a direction exactly opposite to the a. applied force d. normal force b. net force e. motion c. gravitational force

16. The amount of work done to stop a bullet travelling through a tree trunk a distance of 50 cm with a force of 2.00 x 102 N is a. –4.00 x 102 J d. –1.00 x 102 J b. +4.00 x 102 J e. +1.00 x 104 J c. +1.00 x 102 J

17. A 15-kg load of groceries is lifted up from the ground to the fifth floor of an apartment building. Each floor is 5.00 m high. The potential energy of the groceries with respect to the second floor is a. 3.68 x 103 J d. 2.20 x 103 J b. 2.94 x 103 J e. 0 J c. 7.5 x 101 J

18. A 40.0-kg girl rides her 0.50-kg skateboard. She starts from rest and at a constant acceleration reaches 3.0 m/s in 10 s on a horizontal surface. How much power did she use? a. 6.1 x 101 W d. 1.3 W b. 1.2 x 103 W e. 18 W c. 0 W

19. The amount of work an 118-W electric mower can do in 3.0 min is a. 3.5 x 102 J d. 2.1 x 104 J b. 0 J e. 3.9 ´ J c. 2.5 x 10-2 J

20. The shortest time interval in which a wave motion completely repeats itself (i.e., makes one complete vibration or oscillation) is called the a. amplitude d. frequency b. period e. speed c. wavelength

21. A bob on a vertical spring bounces up and down to produce a longitudinal wave in the spring. If the distance in height between the bob's highest and lowest position is 12 cm, what is the amplitude of the generated wave? a. 3.0 cm d. 24 cm b. 6.0 cm e. 48 cm c. 12 cm

22. An object completes 240 cycles in 15 s. What is its frequency, in hertz? a. 16 Hz d. 15 Hz b. 0.063 Hz e. 3600 Hz c. 240 Hz

23. The universal wave equation, , applies to which of the following wave types? a. water d. light b. sound e. all of the above c. radio waves

24. A sound wave with a frequency of 256 Hz, travelling at 340 m/s has a wavelength of a. 1.33 cm d. 1.33 m b. 0.75 m e. 87 km c. 0.75 cm

25. A guitar string produces a musical note with a wavelength of 75 cm. If the speed of sound in air is 344 m/s, what is the frequency of the note? a. 460 Hz d. 4.6 Hz b. 0.22 Hz e. 26 kHz c. 22 Hz

26. Waves can bend as they travel through small openings or past corners. This is due to the property called a. diffraction d. resonance b. refraction e. interference c. reflection

27. Waves can bend as they change speeds when travelling through different mediums. This is due to a property called a. diffraction d. resonance b. refraction e. interference c. reflection