Equations:



1. A phonograph turntable in the xz plane is rotating clockwise as viewed from above. The vector that represents the torque with which the motor turns the table is

a) [pic]

b) [pic]

c) [pic]

d) [pic]

e) [pic]

2. As a particle with a velocity [pic]in the negative x direction passes through the point (0,0,1), it has an angular velocity relative to the origin that is best represented by vector

a) [pic]

b) [pic]

c) [pic]

d) [pic]

e) zero

3. A wheel I set spinning and is then by a rope placed at one end of the axle. If the wheel is spinning as shown, the angular momentum of the wheel could be represented by the vector

a) [pic]

b) [pic]

c) [pic]

d) [pic]

e) [pic]

4. Particles 1, 2, and 3 have equal masses and equal speeds. The angular momentum with respect to the origin for these three masses is

a) the same for each particle.

b) greatest for particle 1.

c) greatest for particle 2.

d) greatest for particle 3.

e) least for particle 2.

5. If the angular momentum of a system is constant, which of the following statements must be true?

a) No torque acts on any part of the system.

b) A constant torque acts on each part of the system.

c) Zero net torque acts on each part of the system.

d) A constant external torque acts on the system.

e) Zero net torque acts on the system.

6. The angular momentum of a body about a particular axis as a function of time is shown in the graph. The external torque acting on the body along this axis at t = 2s is

a) 0

b) 5 N-m

c) 10 N-m

d) 20 N-m

e) 40 N-m

7. A spinning bicycle wheel is supported as shown by a line fastened to one end of its axle. The resultant torque acting on the wheel lies along which of the following axles?

a) x

b) y

c) -y

d) z

e) -z

8. A woman sits on a stool that can turn friction-free about its vertical axis. She is handed a spinning bicycle wheel that has an angular momentum [pic] and she turns it over (that is, through 180˚). She thereby acquires an angular momentum of magnitude

a) 0

b) [pic]

c) [pic]

d) [pic]

e) [pic]

9. A man stands on the center of a platform that is rotating on frictionless bearings at a speed of 1.00 rad/s. Originally his arms are outstretched and he holds a 4.54-kg mass in each hand. He then pulls the weights in toward his body. Assume the moment of inertia of the man, including his arms, to remain constant at 5.42 kg-m2. If the original distance of the weights from the axis is 0.914 m and their final distance is 0.305 m, the final angular velocity is

a) 1.14 rad/s.

b) 1.27 rad/s.

c) 1.58 rad/s.

d) 2.08 rad/s.

e) 7.70 rad/s.

10. A woman sits on a spinning piano stool with her arms folded. When she extends her arms, which of the following occurs?

a) She increases her moment of inertia, thereby increasing her angular speed.

b) She increases her moment of inertia, thereby decreasing her angular speed.

c) She decreases her moment of inertia, thereby increasing her angular speed.

d) She decreases her moment of inertia, thereby decreasing her angular speed.

e) Both her moment of inertia and her angular speed remain constant.

11. A wheel of moment of inertia 0.136 kg-m2 is spinning with an angular speed of 5000 rad/s. A torque is applied about an axis perpendicular to the spin axis. If the applied torque has a magnitude of 67.8 N-m, the angular velocity of precession will be

a) 1.00 rad/s

b) 0.100 rad/s

c) 10.0 rad/s

d) 100 rad/s

e) 1000 rad/s

12. A certain airplane engine rotates counterclockwise when viewed from aft (that is, from the back of the airplane). When the plane turns to the left,

a) The engine makes it turns faster than when it turns to the right.

b) The engine makes it turn slower than when it turns to the right.

c) It tends to dive.

d) It tends to climb.

e) The engine has no effect on the turn.

13. A solid cylinder is spinning counterclockwise about a longtitudinal axis when a net torque t is applied, as shown. The cylinder

a) speeds up.

b) Slows down.

c) Precesses about a vertical axis.

d) Precesses about a horizontal axis.

e) Does none of these.

14. A wheel is set spinning and then is hung by a rope placed at one end of the axle. The precession vector of the spinning wheel points in the direction of

a) z

b) -y

c) –z

d) -x

e) y

15. A spinning bicycle wheel with a loaded rim (essentially a hoop) is supported by a line at one end of its axle. The radius of the wheel is 0.305 m, and the wheel has a mass of 3.63 kg. It is spinning at 80.0 rad/s, and the center of mass is 15.2 cm from the point of support. The angular velocity of precession is

a) 0.0125 rad/s

b) 0.0318 rad/s

c) 0.200 rad/s

d) 0.100 rad/s

e) 0.625 rad/s

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download