Tennessee State University

Tennessee State University Dept. of Physics & Mathematics PHYS 2110 CF SP 2009 Name___________________________________ 30% Time is 2 hours. Cheating ...
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Tennessee State University Dept. of Physics & Mathematics

PHYS 2110 CF SP 2009 Name___________________________________ 30% Time is 2 hours. Cheating will give you an F-grade. Other instructions will be given in the Hall. MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) A 0.13-kg block on a horizontal frictionless surface is attached to a spring whose force constant is 500 N/m. The block is pulled from its equilibrium position at x = 0 m to a displacement x = +0.080 m and is released from rest. The block then executes simple harmonic motion along the x-axis (horizontal). When the displacement is x = 0.018 m, the kinetic energy of the block is closest to: A) 1.7 J B) 1.6 J C) 1.8 J D) 1.4 J E) 1.5 J

1)

2) Water flows through a pipe. The diameter of the pipe at point B is larger than at point A. Where is the speed of the water greater? A) point A B) point B C) same at both A and B D) Cannot be determined from the information given.

2)

3) Which of the following is a FALSE statement? A) Waves transport energy and matter from one region to another. B) In a transverse wave the particle motion is perpendicular to the velocity vector of the wave. C) A wave in which particles move back and forth in the same direction as the wave is moving is called a longitudinal wave. D) Not all waves are mechanical in nature. E) The speed of a wave and the speed of the vibrating particles that constitute the wave are different entities.

3)

Situation 16.4 A car on a road parallel to and right next to a railroad track is approaching a train. The car is traveling eastward at 30.0 m/s while the train is going westward at 50.0 m/s. There is no wind, and the speed of sound is 344 m/s. The car honks its horn at a frequency of 1.00 kHz as the train toots its whistle at a frequency of 1.50 kHz.

4) In Situation 16.4, the frequency that the car's driver hears from the train's whistle is closest to: A) 1.91 kHz B) 1.95 kHz C) 1.18 kHz D) 1.15 kHz E) 1.20 kHz 5) A turbine blade rotates with angular velocity the blade at t = 9.30 s? A) -9.16 rad/s2

(t) = 2 - 0.6t2 . What is the angular acceleration of

B) -49.9 rad/s2 C) -24.9 rad/s2

D) -5.58 rad/s2 E) -11.2 rad/s2

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4)

5)

6) At any angular speed, a certain uniform solid sphere of diameter D has half as much rotational kinetic energy as a certain uniform thin-walled hollow sphere of the same diameter when both are spinning about an axis through their centers. If the mass of the solid sphere is M, the mass of the hollow sphere is: A) 5/3 M B) 5/6 M C) 2 M D) 6/5 M E) 3/5 M

6)

7) Which of the following is an accurate statement? A) A particle moving in a straight line with constant speed necessarily has zero angular momentum. B) If the torque acting on a particle is zero about an arbitrary origin, then the angular momentum of the particle is also zero about that origin. C) Consider a planet moving in a circular orbit about a star. Even if the planet is spinning it is not possible for its total angular momentum to be zero. D) The angular momentum of a moving particle depends on the specific origin with respect to which the angular momentum is calculated. E) If the speed of a particle is constant, then the angular momentum of the particle about any specific origin must also be constant.

7)

Figure 10.5

8) In Fig. 10.5, a mass of 47.47 kg is attached to a light string, which is wrapped around a cylindrical spool of radius 10 cm and moment of inertia 4.00 kg · m2 . The spool is suspended from the ceiling,

8)

9) A uniform disk has a mass of 2.6 kg and a radius of 0.75 m. The disk is mounted on frictionless bearings and is used as a turntable. The turntable is initially rotating at 60 rpm. A thin-walled hollow cylinder has the same mass and radius as the disk. It is released from rest, just above the turntable, and on the same vertical axis. The hollow cylinder slips on the turntable for 0.20 s until it acquires the same final angular velocity as the turntable. The loss of kinetic energy of the system is closest to: A) 9.6 J B) 4.9 J C) 6.5 J D) 8.1 J E) 11 J

9)

and the mass is then released from rest a distance 4.80 m above the floor. How long does it take to reach the floor? A) 3.04 s B) 6.03 s C) 1.03 s D) 2.87 s E) 4.28 s

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Figure 11.3

10) A 10-kg uniform ladder, 5.0 m long, is placed against a smooth wall at a height of 3.1 m. The base of the ladder rests on a rough horizontal surface whose coefficient of static friction is 0.40. An 80-kg block is suspended from the top rung of the ladder, close to the wall. In Fig. 11.3, the force exerted on the wall by the ladder is closest to: A) 1500 N B) 660 N C) 1100 N D) 830 N E) 1300 N

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10)

Figure 11.9

11) In Fig. 11.9, the Achilles tendon exerts a force F = 720 N. What is the torque it exerts about the ankle joint? A) 21.2 N · m B) 25.9 N · m C) 36.0 N · m D) 12.2 N · m E) 16.2 N · m

11)

12) An irregularly shaped object (such as a wrench) is dropped from rest and feels no air resistance. It will A) accelerate and spin until its center of gravity reaches its highest point. B) accelerate and turn about its center of gravity with uniform angular acceleration. C) accelerate and turn until its center of gravity reaches its lowest point. D) accelerate and turn about its center of gravity with uniform angular speed. E) accelerate but will not spin.

12)

13) Suppose that a person can jump straight up a distance of 61 cm on the surface of the earth. How small would a planet have to be so that the person could jump completely off (i.e., jump up and not come down)? Assume the earth's radius is 6380 km and that the small planet has the same density as the earth. A) 1.98 km B) 0.0265 km C) 0.761 km D) 62.4 km E) 1230 km

13)

14)

14)

A 2.0-kg block slides on a frictionless 15° inclined plane. A force acting parallel to the incline is applied to the block. The acceleration of the block is 1.5 m/s2 down the incline. What is the applied force?

A) C)

B) D)

2.1 N up the incline 8.1 N down the incline

3.0 N up the incline 8.1 N up the incline

3.0 N down the incline E) 15) Only two forces act on a 3.0-kg mass. One of the forces is 9.0 N east, and the other is 8.0 N in the direction of 62 north of west. What is the magnitude of the acceleration of the mass in m/s2 ?

A)

2.0

E)

2.9

B)

C) 3.3

2.4 4

D) 5.7

15)

Figure 5.13

16) In Fig. 5.13, two wooden blocks of 0.30 kg mass each are connected by a string that passes over a pulley. One block slides on a horizontal table, while the other hangs suspended by the string, as shown in the sketch. At t = 0, the suspended block is 0.80 m over the floor, and the blocks are released from rest. After 2.5 s, the suspended block reaches the floor. What is the coefficient of kinetic friction between the table and the sliding block? A) 0.65 B) 0.52 C) 0.84 D) 0.95 E) 0.35

16)

17) A 3.00-kg ball swings rapidly in a complete vertical circle of radius 2.00 m by a light string. The ball moves so fast that the string is always taut. As the ball swings from its lowest point to its highest point: A) The work done on it by gravity is +118 J and the work done on it by the tension in the string is -118 J. B) The work done on it by gravity is -118 J and the work done on it by the tension in the string is zero. C) The work done on it by gravity is -118 J and the work done on it by the tension in the string is +118 J. D) The work done on it by gravity and the work done on it by the tension in the string are both equal to zero. E) The work done on it by gravity and the work done on it by the tension in the string are both equal to -118 J.

17)

18) A 60-kg person drops from rest a distance of 1.20 m to a platform of negligible mass supported by a stiff spring. The platform drops 6 cm before the person comes to rest. What is the spring constant of the spring? A) 4.12 × 105 N/m

18)

B) 5.45 × 104 N/m C) 2.56 × 105 N/m D) 3.92 × 105 N/m E) 8.83 × 104 N/m

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19) If the resultant force acting on a 2.0-kg object is equal to (3i + 4j) N, what is the change in kinetic energy as the object moves from (7i — 8j) m to (11i —5j) m? A)

+24 J

B)

+28 J

C)

+32 J

D)

19)

+60J

20) Two identical balls are thrown directly upward, ball A at speed v and ball B at speed 2v, and they feel no air resistance. Which statement about these balls is correct? A) The balls will reach the same height because they have the same mass and the same acceleration. B) At their highest point, the acceleration of each ball is instantaneously equal to zero because they stop for an instant. C) Ball B will go four times as high as ball A because it had four times the initial kinetic energy. D) At its highest point, ball B will have twice as much gravitational potential energy as ball A because it started out moving twice as fast. E) Ball B will go twice as high as ball A because it had twice the initial speed.

20)

Figure 8.1

21) A block of mass m = 2.9 kg, moving on a frictionless surface with a speed v i = 4.1 m/s, makes a

perfectly elastic collision with a block of mass M at rest. After the collision, the 2.9 block recoils with a speed of v f = 0.8 m/s. In Fig. 8.1, the speed of the block of mass M after the collision is closest to:

A) 3.7 m/s

B) 3.3 m/s

C) 4.1 m/s

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D) 4.5 m/s

E) 4.9 m/s

21)

Figure 8.3

22) In Fig. 8.3, a bullet of mass 0.01 kg moving horizontally strikes a block of wood of mass 1.5 kg which is suspended as a pendulum. The bullet lodges in the wood, and together they swing upward a distance of 0.40 m. What was the velocity of the bullet just before it struck the wooden block? The length of the string is 2 meters. A) 250 m/s B) 66.7 m/s C) 646 m/s D) 423 m/s E) 366 m/s

22)

23) The following conversion equivalents are given: 1 gal = 231 in3 1 ft = 12 in 1 min = 60 s

23)

A pipe delivers water at the rate on 42 gal/min. The rate in ft3 /s, is closest to: A) 0.068 B) 0.077 C) 0.094 D) 0.060

E) 0.085

24) What is the magnitude of the sum of the following vectors? A = i +5 j - k A) 8.43

B =4i - j - 5k C = -i + j B) 8.77 C) 3.00 D) 13.09

24) E) 9.85

25) Which of the following situations is impossible? A) An object has velocity directed east and acceleration directed east. B) An object has constant nonzero velocity and changing acceleration. C) An object has constant nonzero acceleration and changing velocity. D) An object has zero velocity but nonzero acceleration. E) An object has velocity directed east and acceleration directed west.

25)

26) A ball is projected upward at time t = 0.0 s, from a point on a roof 90 m above the ground. The ball rises, then falls and strikes the ground. The initial velocity of the ball is 82.4 m/s. Consider all quantities as positive in the upward direction. The velocity of the ball when it is 73 m above the ground is closest to: A) -101 m/s B) -51 m/s C) -84 m/s D) -68 m/s E) -34 m/s

26)

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27) Two particles, A and B, are in uniform circular motion about a common center with the same radial acceleration. Particle A moves in a circle of 8.9 m radius with a periods of 4.3 s. Particle B moves with a speed of 2.9 m/s. The period of the motion of particle B is closest to: A) 1.1 s B) 1.0 s C) 0.84 s D) 0.96 s E) 0.90 s

27)

28) A cork shoots out of a champagne bottle at an angle of 34.0° above the horizontal. If the cork travels a horizontal distance of 1.30 m in 1.40 s, what was its initial speed? A) 7.44 m/s B) 2.11 m/s C) 3.75 m/s D) 1.12 m/s E) 4.22 m/s

28)

Figure 4.6

29) A 5.1-kg box is held at rest by two ropes that form 30° angles with the vertical. An external force F acts vertically downward on the box. The force exerted by each of the two ropes is denoted by T. A force diagram, showing the four forces that act on the box in equilibrium, is shown in Fig. 4.6. The magnitude of force F is 920 N. The magnitude of force T is closest to: A) 560 N B) 971 N C) 486 N D) 388 N E) 777 N

29)

30) Consider what happens when you jump up in the air. Which of the following is the most accurate statement? A) It is the upward force exerted by the ground that pushes you up, but this force can never exceed your weight. B) You are able to spring up because the earth exerts a force upward on you that is stronger than the downward force you exert on the earth. C) Since the ground is stationary, it cannot exert the upward force necessary to propel you into the air. Instead, it is the internal forces of your muscles acting on your body itself that propels the body into the air. D) When you push down on the earth with a force greater than your weight, the earth will push back with the same magnitude force and thus propel you into the air. E) When you jump up the earth exerts a force F1 on you and you exert a force F2 on the earth.

30)

You go up because F1 > F2 .

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