Rotational Motion and Rotational Dynamics

A cave dweller rotates a pebble in a sling with a radius of 0.30 m clockwise through an arc length of 0.96 m. What is the angular displacement of the pebble?

• 1.6 rad

• -1.6 rad

• 3.2 rad

• -3.2 rad

A fixed point, around which something turns, perpendicular to the rotation.

• axis of rotation

• radius

• diameter

• radian

Tags

NGSS.MS-PS2-2

A quantity that measures the ability of a force to rotate an object  around some axis

• linear speed

• angular speed

• torque

• centrifugal speed

A wrench is used to tighten a nut as shown in the figure. A 12-N force is applied 7.0 cm from the axis of rotation. What is the magnitude of the torque due to the applied force?

• 1.71 Nm

• 0.84 Nm

• 1.71 Nm

• 0.58 Nm

• 84 Nm

What force does not cause any torque?

• Force perpendicular to the fulcrum.

• Force horizontal to the planck.

• Force slightly off center of the fulcrum

• Forces at a 45 degree angle to the fulcrum, and not on the fulcrum

A person sits on a freely spinning lab stool that has no friction in its axle. When this person extends her arms,

• her moment of inertia increases and her angular speed decreases.

• her moment of inertia decreases and her angular speed increases.

• her moment of inertia increases and her angular speed increases.

• her moment of inertia increases and her angular speed remains the same.

Which of these gives rotational kinetic energy?

• a

• b

What does this formula measure?

• moment of inertia

• impulse

• electric current

• angular momentum

A solid sphere and a hollow sphere of the same mass and radius are released from the top of an inclined plane. Which one reaches the bottom first?

• A) Solid sphere

• B) Hollow sphere

• C) Both reach at the same time

• D) Cannot be determined

Tags

NGSS.HS-PS2-1