We've learned about circular motion and how to use the tangential description of motion. And we've learned about rotational motion and how to use the angular description of motion.

But there are many scenarios where we might need to combine them, or convert from one description to the other. Imagine a fly lands on the edge of a spinning record. Is the fly in circular motion or rotational motion? What concepts and equations can we use to describe its motion?

In this lesson we'll talk about the difference between an object's physical motion and the description of motion. Then we'll dive into the ways we can describe objects in circular motion and rotational motion. Finally, we'll learn how to convert between these descriptions using the relationship between arc lengths and angles.

We'll end up with a list of equations that we can use to convert between an arc length and an angle, tangential velocity and angular velocity, and tangential acceleration and angular acceleration.

Multiple-Choice Questions

Answers

Free-Response Questions

Circular motion

• 2024 Q1 - - Block sliding on a track with loops, forces, FBDs, circular motion, energy
• 2023 Q3 - - Block and spring rotating about axle, circular motion, centripetal force, FBDs
• 2018 Q1 - - Spacecraft in circular orbit, circular motion, forces, FBDs, law of gravitation

Rotational motion

• 2024 Q3 - - Beam attached to a wall with a string, forces, FBDs, tension, rotational motion, torque
• 2023 Q4 - - Block hanging from string around pulley, rotational motion, torque, angular momentum, energy, work
• 2023 Q5 - - Sphere and rod rotating about axle, rotational motion, torque, energy, work
• 2022 Q3 - - (Experimental design) Block hanging from string around wheel, energy, rotational motion
• 2021 Q4 - - Cylinder rolls and block slides down an incline, energy, work, rotational motion
• 2021 Q5 - - 2 blocks hanging from strings on pulleys, rotational motion, torque
• 2019 Q2 - - Pulley system with 2 blocks, kinematics, forces, FBDs, tension, rotational motion
• 2018 Q3 - - Disk spinning on axle, rotational motion, torque
• 2017 Q3 - - Disk collides with pivoting rod, rotational motion, torque, angular momentum

• Michel van Biezen - Rotational Motion

We've learned about circular motion and how to use the tangential description of motion. And we've learned about rotational motion and how to use the angular description of motion.

But there are many scenarios where we might need to combine them, or convert from one description to the other. Imagine a fly lands on the edge of a spinning record. Is the fly in circular motion or rotational motion? What concepts and equations can we use to describe its motion?

In this lesson we'll talk about the difference between an object's physical motion and the description of motion. Then we'll dive into the ways we can describe objects in circular motion and rotational motion. Finally, we'll learn how to convert between these descriptions using the relationship between arc lengths and angles.

We'll end up with a list of equations that we can use to convert between an arc length and an angle, tangential velocity and angular velocity, and tangential acceleration and angular acceleration.