PHYSICS 2204 UNIT 3 WORK AND ENERGY Section

PHYSICS 2204 UNIT 3: WORK AND ENERGY Section 3. 3 – Hooke’s Law and Simple Harmonic Motion

Definition Motion that obeys Hooke’s law (F = -kx) is called simple harmonic motion (SHM). Examples: Mass on a Spring Swinging Pendulum

Definition In physics you will here the term oscillate a lot.

Mass on a Spring - Stages

Max Stretch

Equilibrium

Max Compression

Theory vs. Reality In theory, a mass on a spring will oscillate forever. However, in reality the mass’ oscillation will decrease and eventually the mass will return to equilibrium. Why?

Recall Hooke’s Law. . . F = -kx

Example A 0. 5 kg puck is connected to the side of an air table by a spring. A force of 1. 4 N is applied to pull the puck 8. 0 cm to the right. Then the puck is released. a) What is the maximum acceleration of the puck? b) What is the acceleration of the puck as it passes through its original rest position?

Energy and SHM At the equilibrium position, the elastic potential energy equals the kinetic energy of the mass.

Example A spring with a spring constant of 80. 0 N/m has a 1. 5 kg block attached to one end. If the block is pulled out 0. 50 m from its rest position, and released, what is its speed when it returns to the equilibrium position? Assume there is no friction.

Homework Page 376 in the Textbook #104, 105 a) b)