WorksheetsRotational KE and L
Total questions: 15
Worksheet time: 17mins
A person sits on a freely spinning lab stool (no friction). When this person extends her arms,
Her moment of inertia decreases and her angular velocity increases
Her moment of inertia decreases and her angular velocity decreases
Her moment of inertia increases and her angular velocity decreases
Her moment of inertia increases and her angular velocity increases
A solid cylinder and a hollow cylinder have the same mass and the same radius. Which statement is true concerning their moment of inertia about an axis through the exact center of the flat surfaces?
The hollow cylinder has the greater moment of inertia
The solid cylinder has the greater moment of inertia
Both cylinders have the same moment of inertia
It depends how much material is removed from the hollow cylinder
In translational motion, mass is a measure of an object’s acceleration in response to a force. What is the rotational analog of mass?
torque
moment of inertia
angular acceleration
angular momentum
What is the angular momentum of the 2m-long, 2kg bar rotating about its center at 6 rad/s?
24 kgm2/s
2 kgm2/s
12 kgm2/s
4 kgm2/s
Three objects, A, B, and C all have the same mass and radius but different moments of Inertia. All three are released from the top of a ramp, which will reach the bottom of the ramp first?
A
B
C
They all tie
The turntable in a microwave oven has a moment of inertia of 0.040 kgm2 and rotates continuously, making a complete revolution every 4.0 seconds. What is its kinetic energy?
0.099 J
0.314 J
0.05 J
0.0013 J
A ball with diameter 10. cm rolls without slipping on a horizontal table top. The moment of inertia of the ball is 2.2 × 10-3 kgm2 and its translational speed is 0.45 m/s.
What is its angular speed about its center?
9 rad/s
0.09 rad/s
0.045 rad/s
4.5 rad/s
Two uniform disks have the same radius but different masses: disk 1 has a mass M, disk 2 has a mass 2M. What is the ratio of the moment of inertia of the first disk to the second disk?
1:4
1:2
2:1
4:1
Two uniform disks have the same radius but different radii: disk 1 has a radius R and disk 2 has a radius 2R. What is the ratio of the moment of inertia of the first disk to the second disk?
1:4
1:2
2:1
4:1
A ramp race between a Hoop, a Sphere, and an Ice cube takes place. All objects have the same mass, start from the same height at the same time. The Ice cube slides down the ramp with zero friction. Which object wins?
Ice Cube
Sphere
Hoop
They all tie
An energy-storage system based on a flywheel (a rotating disc) can store a maximum of 4 x 106 J when the flywheel is rotating at 20,000 RPM. What is the moment of inertia of the flywheel?
0.02 kgm2
1.83 kgm2
0.46 kgm2
3820 kgm2
An ice skater performs a fast spin by pulling her outstretched arms down and close to her body. What happens to her angular momentum with respect to the axis of rotation?
increases
decreases
stays the same
depends on initial rotational velocity
An ice skater performs a fast spin by pulling her outstretched arms down and close to her body. What happens to her rotational Kinetic Energy?
increases
decreases
stays the same
depends on initial rotational velocity
A thin rod of length r can pivot about its left end. What is the magnitude of the angular momentum of the rod immediately after it is struck by the ball?
(pf - pi)*r
(pf + pi)*r
(pf - pi)
(pf + pi)
Two boys of equal mass standing halfway to the edge on a turntable that is freely rotating at angular speed ωi. They then walk to the positions shown in the right figure. The final angular speed ωf is:
Less than ωf
Greater than ωf
Equal to ωf
Cannot be determined without knowing the mass of the boys and turntable
