Wednesday, Jan 14, 2009 - Blocks 1 and 3

Collected RA 7.1
Handed back RA 7.1.
Expanded chart showing correspondence between linear motion and rotational motion to include forces and torques. Used this to lead into going over RA 7.1.

Talked about the energy stored in diatomic molecules and monoatomic gases.

Showed demo tossing book into the air. Alan W said you could rank the size of the rotational inertia by the length of the axis that intersected the book - the greater the length, the smaller the rotational inertia. Very astute. Showed that rotation about the middle axis is unstable.

Introductory lecture on Uniform Circular Motion.
Showed that acceleration and centripetal force are directed towards center and thus centripetal. Derived the centripetal force equation. Did examples on calculating period, frequency, linear velocity, centripetal acceleration, centripetal force.

In problem solving strategy, always choose one coordinate axis in the direction of the acceleration. Showed some examples using "zap".

Handed out RA 7.4. Due tomorrow along with Circular Motion Lab.