Section 08: Center of Mass, Circular and Rotational Motion

Goal: To explain that centripetal and not centrifugal force accounts for circular motion and how your frame of reference affects your perception of circular motion.

Objectives: Students will be able to:

- distinguish between rotate and revolve.

- distinguish between linear speed (tangential speed) and rotational speed, and explain what each depends on.

- give examples of centripetal force in different horizontal conditions (e.g. flat track, banked track, cylinders, objects on a string).

- describe the resulting motion of an object if the centripetal force acting on it ceases.

- explain why it is incorrect to say that a centrifugal force pulls outward on an object in circular motion and why a physicist would label this a fictitious force.

- describe how a simulated gravitational acceleration can be produced in a space colony.

- Define and calculate angular displacement, angular velocity, and angular acceleration and relate these quantities to linear measures of velocity and acceleration for circular motion.

- Calculate period, tangential velocity, centripetal acceleration, centripetal force

Goal: To understand the concept of center of gravity, and how it affects stability of an object.

Objectives: Students will be able to:

- describe center of gravity and compare and contrast it with Center of Mass

- describe how a plumb line and bob can be used to find the center of gravity of an irregularly shaped object.

- given the location of the center of gravity and the area of support of an object, predict whether the object will topple.

- distinguish among stable equilibrium, unstable equilibrium, and neutral equilibrium.

- give examples of how a human is affected by the need to keep the body’s center of gravity over the support base.

Goal: To understand how rotational motion and angular momentum are affected by Torque.

Objectives: Students will be able to:

- Define Torque and lever arm and be able to determine the net torque acting on an object.

- Define and explain rotational inertia and calculate it for simple shapes.

- Define and calculate angular momentum and explain how it is affected by rotational inertia.

- Describe conservation of angular momentum and relate it to conservation of linear momentum.

Labs: Circular Motion Lab, Rotational KE, torque (Parts 1-4).

Worksheets: See below list.

Conceptual Development Worksheets ("Conceptual Development" will be in the title).

Reading Assignment: Chapter 8

Extra Credit: None at this time. If you have a proposal for one, speak to me first and if approved I'll offer it to everyone.

Class Updates/Test/Quiz Schedule: Refer to the posted SOE.