Term 2 Week 5 2016

Homework

Make sure that you have completed:

• Ex 1, p.25-28, Translational Motion
• Q2, Handout, Lab Exercise

New Homework

• Ex 2, p. 41-45, Rotational Motion

Rotational Momentum (Angular Momentum)

For a point mass L = Pr

Linear Momentum times the radius distance between the point mass and the axis of rotation

Momentum: Rotational Linear

Equation: L = I⍵ P = mv

Units: kgm2s-1  kgms-1

• Rotational Momentum and Linear Momentum have different units so they cannot be equated with each other and are independent of each other.
• Rotational Momentum obeys the same law of conservation that Linear Momentum obeys. In the absence of outside forces, total momentum is always conserved.

Precession

Egg Spinning

Rotational Kinetic Energy

Energy: Rotational Linear

Equation: Ek(rot) = ½I⍵2 Ek(lin) = ½mv2

Units: Joule Joule

• Rotational Kinetic Energy and Linear Kinetic Energy have the same unit so they can be equated with each other and are interdependent on each other.
• The law of conservation of total energy can be applied with all types of energy. You will be using mostly gravitational potential, linear kinetic, and rotational kinetic energies.

• Total Kinetic Energy = Ek(rot) + Ek(lin)

= (½I⍵2) + (½mv2 )