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

Please return you optional homework

A bullet of mass m is fired with velocity of magnitude into a block of mass M. The block is connected to a spring constant k and rests on a frictionless surface. Find the velocity of the block as a function of time. (Assume the bullet comes to rest infinitely quickly in the block, i.e. during the collision the spring doesn’t get compressed.)

Exercise 4 k1k1 k2k2 m x=0

Resonance amplitude

Frames of reference

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 101 Richardson, 10 am- noon, Friday, December 11. Help Sessions: Tuesday (by appointment) Wednesday, December 9th, 2pm 203 MPHYS