Unit 4 - Rotational Mechanics & Gravitation
This is a unique and diverse unit - it encompasses 3 chapters which relate somewhat. We will only cover material in the book that is directly related to the AP standards. This unit covers rotational, torque and Universal Law of Gravitation. AP Physics B objectives don't have us covering center of mass but to understand rotation, it is important to understand center of mass, therefore one of the first thing we must understand is the center of mass concept. Watch video lesson first and then do the notes to understand them better. One topic that is not covered will be the moment of inertia - if we have extra time take a look at it.
Objective 1: (Section 10.1 – 10.4) Rotation
A. Students should understand the uniform circular motion of a particle, so they can:
1. Relate the radius of the circle and the speed or rate of revolution of the particle to the magnitude of the centripetal acceleration
2. Describe the direction of the particle’s velocity and acceleration at any instant during the motion.
3. Determine the components of the velocity and acceleration vectors at any instant, and sketch or identify graphs of these quantities.
4. Motion in a horizontal circle (e.g., mass on a rotating merry-go-round, or car rounding a banked curve).
5. Motion in a vertical circle (e.g., mass swinging on the end of a string, cart rolling down a curved track, rider on a Ferris wheel).
Objective 2: (Section 11-1-11-3, 11-6) Torque and Rotational Statics
A. Students should understand the concept of torque, so they can:
1. Calculate the magnitude and direction of the torque associated with a given force.
2. Calculate the torque on a rigid object due to gravity.
3. State the conditions for translational and rotational equilibrium of a rigid object.
4. Apply these conditions in analyzing the equilibrium of a rigid object under the combined influence of a number of coplanar forces
applied at different locations.
Objective 3: (Section 12.1-2) Newton’s Law of Gravity
A. Students should know Newton’s Law of Universal Gravitation, so they can:
1. Determine the force that one spherically symmetrical mass exerts on another.
2. Determine the strength of the gravitational field at a specified point outside a spherically symmetrical mass.
Objective 4: (Section 12.3) Orbits of planets and satellites
A. Students should understand the motion of an object in orbit under the influence of gravitational forces, so they can: (circular orbit)
1. Recognize that the motion does not depend on the object’s mass; describe qualitatively how the velocity, period of revolution, and
centripetal acceleration depend upon the radius of the orbit; and derive expressions for the velocity and period of revolution in such
an orbit.
2. Derive Kepler’s Third Law for the case of circular orbits.
Objective 1: (Section 10.1 – 10.4) Rotation
A. Students should understand the uniform circular motion of a particle, so they can:
1. Relate the radius of the circle and the speed or rate of revolution of the particle to the magnitude of the centripetal acceleration
2. Describe the direction of the particle’s velocity and acceleration at any instant during the motion.
3. Determine the components of the velocity and acceleration vectors at any instant, and sketch or identify graphs of these quantities.
4. Motion in a horizontal circle (e.g., mass on a rotating merry-go-round, or car rounding a banked curve).
5. Motion in a vertical circle (e.g., mass swinging on the end of a string, cart rolling down a curved track, rider on a Ferris wheel).
Objective 2: (Section 11-1-11-3, 11-6) Torque and Rotational Statics
A. Students should understand the concept of torque, so they can:
1. Calculate the magnitude and direction of the torque associated with a given force.
2. Calculate the torque on a rigid object due to gravity.
3. State the conditions for translational and rotational equilibrium of a rigid object.
4. Apply these conditions in analyzing the equilibrium of a rigid object under the combined influence of a number of coplanar forces
applied at different locations.
Objective 3: (Section 12.1-2) Newton’s Law of Gravity
A. Students should know Newton’s Law of Universal Gravitation, so they can:
1. Determine the force that one spherically symmetrical mass exerts on another.
2. Determine the strength of the gravitational field at a specified point outside a spherically symmetrical mass.
Objective 4: (Section 12.3) Orbits of planets and satellites
A. Students should understand the motion of an object in orbit under the influence of gravitational forces, so they can: (circular orbit)
1. Recognize that the motion does not depend on the object’s mass; describe qualitatively how the velocity, period of revolution, and
centripetal acceleration depend upon the radius of the orbit; and derive expressions for the velocity and period of revolution in such
an orbit.
2. Derive Kepler’s Third Law for the case of circular orbits.