**Objectives**

- Define how to measure and calculate changes in angular position (
*angular displacement*) and the time derivatives*angular velocity*and*angular acceleration* - Apply Newton's Laws of Motion to angular motion
- Use the equations of angular motion and demonstrate how they interact with each other

**Describing angular position**

Joint and segmental angles

**Newton's Laws (applied to angular motion)**

- Every body continues in its state of rest, or of uniform angular motion, unless it is compelled to change that state by torques impressed upon it.
- The change of angular motion of an object is proportional to the torque impressed; and is made in the direction of the torque (T=Ia).
- To every action, there is always opposed an equal reaction: or the mutual actions of two bodies upon each other are always equal and directed to contrary parts.

**Equations of angular motion**

**Connection of Linear and Angular Velocity:**

**v = w * r**(Golf example)

**Tangential Acceleration:**The component of of linear acceleration tangent to the circular path of a point on a rotating object

** a**_{T} = a * r

**Centripetal Acceleration:**The linear acceleration directed toward the axis of rotation (Hammer throw)

** a _{r} = w^{ 2} r**

**Angular Momentum** H=Iw

**Angular Inertia** I=mk^{2}

Ice-skating spin