A turntable has a moment of inertia of 3.00 102 kgm2 and spins freely on a frictionless bearing at 25.0 rev/min. A 0.600-kg ball of putty is dropped vertically onto the turntable and sticks at a point 0.100 m from the center. What is the new rate of rotation of the system?
a. 20.8 rev/min b. 22.7 rev/min
c. 33.3 rev/min d. 27.2 rev/min
[Ques. 2] A figure skater on ice with arms extended, spins at a rate of 3.5 rev/s. After he draws his arms in, he spins at 6.0 rev/s. By what factor does the skater's kinetic energy change when he draws his arms in?
a. 2.4 b. 1.7
c. 0.58 d. 0.12
[Ques. 3] An ice skater spins at 3.5 rev/s with his arms are extended. He draws his arms in and spins at 8.3 rev/s. By what factor does his moment of inertia change in the process?
a. 2.4 b. 0.58
c. 0.42 d. 0.12
[Ques. 4] A figure skater with arms initially extended starts spinning on the ice at 3 rad/s. She then pulls her arms in close to her body. Which of the following results?
a. a smaller rotational rate b. a greater rotational rate
c. a greater angular momentum d. a smaller angular momentum
[Ques. 5] A ventilation fan with a moment of inertia of 0.034 kgm2 has a net torque of 0.11 Nm applied to it. If it starts from rest, what angular momentum will it have 9.0 s later?
a. 0.88 kgm2/s b. 0.99 kgm2/s
c. 2.0 kgm2/s d. 3.3 kgm2/s
[Ques. 6] The quantity angular momentum (in terms of the fundamental quantities of mass, length, and time) is equivalent to:
a. MLT2 b. ML2T1.
c. ML2T3 d. ML3T.
[Ques. 7] A 40-kg boy is standing on the edge of a stationary 30-kg circular platform that is free to rotate. The boy tries to walk around the platform in a counterclockwise direction. As he does:
a. the platform doesn't rotate.
b. the platform rotates in a clockwise direction just fast enough so that the boy remains stationary relative to the ground.
c. the platform rotates in a clockwise direction while the boy goes around in a counterclockwise direction relative to the ground.
d. both go around with equal angular velocities but in opposite directions.
[Ques. 8] A solid sphere, a solid cylinder, and a hoop each have the same mass and radius. If they are spinning at the same angular velocity, which one has the greatest angular momentum?
a. the sphere
b. the cylinder
c. the hoop
d. They all have the same angular momentum.
[Ques. 9] A hoop, a solid sphere, and a solid cylinder each have the same mass, radius, and initial speed and are going up the same inclined plane. Which one goes the farthest?
a. the hoop b. the sphere
c. the cylinder d. All go the same distance.
[Ques. 10] A uniform solid sphere rolls down an incline of height 3 m after starting from rest. In order to calculate its speed at the bottom of the incline, one needs to know:
a. the mass of the sphere. b. the radius of the sphere.
c. the mass and the radius of the sphere. d. no more than is given in the problem.
Quick Reply
