Angular Kinetics

Question 1

Angular Kinetics

Answer 1

Forces associated with rotary motion

Question 2

Moment of Inertia

Answer 2

• Inertial property for rotating bodies that increases with both mass and the distance the mass is distributed from the axis of rotation
• I = mk^2 (k = distribution of mass with respect to the axis of rotation)

Question 3

Radius of Gyration

Answer 3

• Distance from the axis to a point where the mass could be concentrated without altering the rotational characteristics
• Not a COG

Question 4

Principal Axes

Answer 4

3 mutually perpendicular axes passing through the total-body COG

Question 5

Principal Moment of Inertia

Answer 5

Total-body movement of inertia relative to one of the principal axes

Question 6

Angular Momentum

Answer 6

• Measured as the product of moment of inertia and angular velocity
• H = Iω (I = moment of inertia)
• H = mk²ω

Question 7

Conservation of Angular Momentum

Answer 7

The total angular momentum of a system remains constant in the absence of external torques

Question 8

Angular Impulse

Answer 8

• Change in angular momentum equal to the product of torque and time interval over which the torque acts
• Angular Impulse = Tt
• Tt = ΔH

Question 9

Angular Analog of Newton’s 1st Law

Answer 9

A rotating body will maintain a state of constant rotational motion unless acted on by an external torque

Question 10

Angular Analog of Newton’s 2nd Law

Answer 10

• A net torque produces angular acceleration of a body that is directly proportional to the torque and inversely proportional to the body’s moment of inertia
• T = Iα

Question 11

Angular Analog of Newton’s 3rd Law

Answer 11

For every torque exerted by one body on another, there is an equal and opposite torque exerted by the second body on the first

Question 12

Centripetal Force

Answer 12

Force directed toward the center of rotation for a body in rotational motion

Question 13

Centripetal Force Equations

Answer 13

• F(c) = mv²/r

- F(c) = mrω²