AP Physics C: Mechanics

1. AP Physics C: Mechanics ROTATION in-class examples

2. Example 1 – Rotational Kinematics A rotating, rigid body makes one complete revolution in 2s. What is its average angular velocity?

3. Example 1 – Rotational Kinematics A rotating, rigid body makes one complete revolution in 2s. What is its average angular velocity? π rad/s

4. Example 2 – Rotational Kinematics The angular velocity of a rotating disk increases from 2 rad/s to 5 rad/s in 0.5 s. What’s the disk’s average angular acceleration?

5. Example 2 – Rotational Kinematics The angular velocity of a rotating disk increases from 2 rad/s to 5 rad/s in 0.5 s. What’s the disk’s average angular acceleration? 6 rad/s2

6. Example 3 – Rotational Kinematics A disk of radius 20 cm rotates at a constant angular velocity of 6 rad/s. How fast does a point on the rim of this disk travel (in m/s)?

7. Example 3 – Rotational Kinematics A disk of radius 20 cm rotates at a constant angular velocity of 6 rad/s. How fast does a point on the rim of this disk travel (in m/s)? 1.2 m/s

8. Example 4 – Rotational Kinematics The angular velocity of a rotating disk of radius 50 cm increases from 2 rad/s to 5 rad/s in 0.5 s. What is the linear tangential acceleration of a point on the rim of the disk during this time interval?

9. Example 4 – Rotational Kinematics The angular velocity of a rotating disk of radius 50 cm increases from 2 rad/s to 5 rad/s in 0.5 s. What is the linear tangential acceleration of a point on the rim of the disk during this time interval? 3 m/s2

10. Example 5 – Rotational Kinematics Derive an expression for centripetal acceleration in terms of angular speed.

11. Example 5 – Rotational Kinematics Derive an expression for centripetal acceleration in terms of angular speed. ac = ω2r

12. Example 6– Rotational Kinematics An object with an initial angular velocity of 1 rad/s rotates with constant angular acceleration. Three second later, its angular velocity is 5 rad/s. Calculate its angular displacement during this time interval.

13. Example 6– Rotational Kinematics An object with an initial angular velocity of 1 rad/s rotates with constant angular acceleration. Three second later, its angular velocity is 5 rad/s. Calculate its angular displacement during this time interval. 9 rad

14. Example 7– Rotational Kinematics Starting with zero initial angular velocity, a sphere begins to spin with constant angular acceleration about an axis through its center, achieving an angular velocity of 10 rad/s when its angular displacement is 20 rad. What is the value of the sphere’s angular acceleration?

15. Example 7– Rotational Kinematics Starting with zero initial angular velocity, a sphere begins to spin with constant angular acceleration about an axis through its center, achieving an angular velocity of 10 rad/s when its angular displacement is 20 rad. What is the value of the sphere’s angular acceleration? 2.5 rad/s2