Unit 5: Rotation

Torque

It is defined as the product of force and the perpendicular distance from the axis of rotation to the line of action of the force.

Newton-meter (Nm) / pound-feet (lb-ft)

unit of torque

moment arm

The perpendicular distance from the axis of rotation to the line of action of the force and is an important factor in determining torque.

Rotational inertia

the property of an object that determines its resistance to rotational motion. It depends on the mass distribution of the object and the axis of rotation.

Parallel Axis Theorem

It states that the moment of inertia of a body about any axis parallel to its center of mass is equal to the moment of inertia about the center of mass plus the product of the mass of the body and the square of the distance between the two axes.

average angular velocity

instantaneous angular velocity

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average angular acceleration

instantaneous angular acceleration

Definition of Rotational Kinetic Energy

rolling motion

For _____ the total kinetic energy is the translational kinetic energy and the rotational kinetic energy

Conservation of Angular Momentum

Equilibrium

____ in rotational motion occurs when an object is not rotating or is rotating at a constant angular velocity.

**Static equilibrium**

This occurs when an object is at rest and the net torque acting on it is zero.

**Dynamic equilibrium**

This occurs when an object is rotating at a constant angular velocity and the net torque acting on it is zero