Non-Rotating Extended Object Model: Torque

Section 6.3

What are the observations of Torque?

It takes less force to loosen a blot if the applied force is farther than the bolt

No rotation since the line of action of the force goes through the pivot point

Oftentimes, the pivot point is an axis of rotation

What is Torque?

Defined to account for this new observation as related to extended object

How is the magnitude of Torque defined?

𝜏

The product of the moment arm 𝑟⊥ and the applied force I F I

The moment arm is?

The perpendicular distance from the pivot point (axis of rotation) to the line of action of the force

The moment arm is the shorter distance from the pivot point to the line of action

To calculate Torque, we must identify?

The moment arm

The Torque depends on?

A well-defined pivot point

What are the sign conventions of Torque?

A counterclockwise Torque is defined as positive

A clockwise Torque is defined as negative

What is the SI unit of Torque?

Newton- meter (N*m)

If a force tends to cause an object to rotate clockwise, what is the dign of the Torque?

Negative

What is Newton’s first law of rotational motion?

An object not rotating will remain not rotating in the absence of a net Torque

𝜏_𝑛𝑒𝑡 = 0

What is rotational inertia?

The tendency of matter to resist changes to its rotation

Whether staying non-rotating

What is the rotational analog of transitional equilibrium?

Translational equilibrium is governed by Newton’s 1st law

Rotational equilibrium is governed by Newton’s 1st law

When both are true, we say there is static equilibrium