Physics 218: Mechanics Instructor: Dr. Tatiana Erukhimova Lecture 42

Please return your optional homework

Simple pendulum How long does it take to return to the equilibrium?

Exercise 4 k1k1 k2k2 m x=0

Resonance amplitude

Frames of reference An airplane flies from Houston to Tokyo in 14 hours, while the return trip takes only 10 hours. Find the wind velocity and plane speed with respect to air, if the distance is 7000 miles. T H W - airplane speed with respect to air.

This means that in the freely-falling elevator cabin you don’t feel any effects of gravity! You and all objects around you experience the same acceleration. In outer space you can imitate the effect of gravity by acceleration.

Newton’s First Law Second Law Third Law

Kinematics is given, you can find If and

Work Energy Theorem

does NOT depend on path!

Mechanical energy is conserved!

Conservation of Momentum If the collision is perfectly elastic, the kinetic energy is conserved!

Circular Motion y x

Conservation of Angular Momentum For symmetrical objects rotating about their axis of symmetry: Second Law: m1 m2 R

Harmonic Motion Resonance:

Final exam: room 204 MPHY, 10:30 am - 12:30 pm, Monday, December 12. Help Sessions: By appointment Thursday, December 8th, 3 pm 204 MPHY