Torque and Moment of Inertia

The figure shows scale drawings of four objects, each of the same mass and uniform thickness, with the mass distributed uniformly. Which one has the greatest moment of inertia when rotated about an axis perpendicular to the plane of the drawing at point P?

• A

• B

• C

• D

Objects A, B, and C all have the same mass, all have the same outer dimension, and are all uniform. Rank these objects in order of their moment of inertia about an axis through its center (shown in blue), from largest to smallest.

• BCA

• ABC

• CAB

• BAC

A solid  metal bar is at rest on a horizontal frictionless surface. It is free to rotate about a vertical axis at the left end. The figures show forces of different magnitudes that are exerted on the bar at different locations. In which case does the bar's angular speed about the axis increase at the fastest rate?

• A

• B

• C

• D

Which of the following must be true for the system of two concentric massless pulleys and two masses shown in the picture for the system to be at equilibrium?

• m₁ = m₂

• m₁R₁ = m₂R₂

• m₁R₂ = m₂R₁

• m₁R₁² = m₂R₂²

Tags

NGSS.HS-PS2-1

A force in a circular direction

• Reciprocating

• Torque

• Speed

• Oscillating

Torque is the product of a force exerted on an object times the lever arm.

• True 

• False

Does a bridge anchored resting on two pillars have any torque?

• No, it isn't moving

• Yes, but it is at equilibrium

• Yes, but it will soon break because of the torque

• No, Bridges can't have torque

The moment of inertia:

• is synonymous with mass

• does not depend on where the mass is located

• resistance to a change in rotational inertia

• more resistance to change = less inertia

When an object is experiencing a net torque

• it is in dynamic equilibrium.

• it is in static equilibrium.

• it is rotating.

• it is translating.

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.