## Kinematics of Rotational Motion

Read this text to see additional worked examples of how to solve problems involving the kinematics of rotational motion.

Example 10.3 shows how to calculate the kinematics of an accelerating fishing reel. Here, equation 10.19 is used to determine how the angular velocity changes with time. This result is used to calculate linear speed. Example 10.4 is an example where the fishing reel decelerates. Using equation 10.19, we solve for time rather than angular velocity. To see more of these types of problems, review Examples 10.5 and 10.6.

### Check Your Understanding

Rotational kinematics has many useful relationships, often expressed in equation form. Are these relationships laws of physics or are they simply descriptive? (Hint: the same question applies to linear kinematics.)

#### Solution

Rotational kinematics (just like linear kinematics) is descriptive and does not represent laws of nature. With kinematics, we can describe many things to great precision but kinematics does not consider causes. For example, a large angular acceleration describes a very rapid change in angular velocity without any consideration of its cause.