Rolling Translation Rotation As you come in please

Rolling = Translation + Rotation • As you come in, please set clicker to channel 44 and then answer the following question (before the lecture starts). Bug the Professor if he forgets to start the clicker software. • Assuming the center of mass of the bicycle and rider are moving at +5 m/s (relative to the ground), how fast is the bottom edge of the wheel moving (relative to the ground)? A. +5 m/s B. 0 m/s C. -5 m/s D. +10 m/s

Topics for Today • Rolling = Translation + Rotation (11 -1) • Forces and Kinetic energy of rolling (11 -2) • The Yo-Yo (11 -3) • Review of cross product (3 -3) • Torque as a vector (11 -4) • Angular momentum as a vector (11 -5)

Rolling = Translation + Rotation •

Forces and Kinetic Energy of Rolling •

Rolling down a ramp •

Rolling down a ramp • Do demo 1 Q 10. 30 - Moments of Inertia - Hoops and Disks • Quiz – which object will reach the bottom first? A. Hoop B. Disk C. Ball D. All are equal

Yo-Yo •

Rolling down a ramp •

Rotational Quantities as Vectors •

Rotational Quantities as Vectors •

Torque as a Vector •

Angular Momentum •

Angular Momentum • Assume that all of the particles in the figure have the same speed. • Quiz – How does the magnitude of the angular momentum of particle 1 compare with that of particle 3? A: L 1 > L 3, B: L 1 = L 3, C: L 1 < L 3 • Quiz – How does the angular momentum of particle 1 compare with that of particle 2? A: L 1 = L 2, B: L 1 = 2 L 2, C: L 1 = -2 L 2

Angular Momentum •