Chaper 15, Oscillation Simple Harmonic Motion (SHM) Spring and Pendulum

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Chaper 15, Oscillation

 Simple Harmonic Motion (SHM)

 Spring and Pendulum

 Damped and Forced Oscillation

Oscillations

Simple Harmonic Motion (SHM)

Period

Simple Harmonic Motion

Angular frequency

Velocity/Acceleration of SHM

Partial Differential Equation (PDF)

Newton’s 2

nd

Law

Newton’s 2 nd law

Hooke’s law

Angular frequency

Period

Pendulum

The Simple Pendulum

Physical Pendulum

(Will derive the equations on the board as examples).

Damped and Forced Oscillations

1. Damped Oscillation

(add a friction force)

2. Forced Oscillation and Resonance

Oscillation will be enhanced significantly when the natural frequency of oscillation = frequency of external force

Example of Solar Filament Oscillation

(Discovered by BBSO/NJIT)

Sample Problem 15 – 1

A block whose mass m is 680 g is fastened to a spring whose spring constant k is 65 N/m. The block is pulled a distance x = 11 cm from its equilibrium position at x = 0 cm on a frictionless surface and released from rest at t = 0.

a) What are the angular frequency, the frequency, and the period of the resulting motion?

b) What is the amplitude of the oscillation?

c) What is the maximum speed v m block when it occurs?

of the oscillating block, and where is the d) What is the magnitude a m of the maximum acceleration of the block?

e) What is the phase constant

 for the motion?

f) What is the displacement function x(t) for the spring block system?

Sample Problem 15– 2

At t = 0, the displacement x(0) of the block in a linear oscillator is –8.50 cm. The block’s velocity v(0) then is

–0.92 m/s, and its acceleration a(0) is +47.0 m/s 2 .

a) What is the angular frequency

 of the system?

b) What are the phase constant

 and the amplitude x m

?

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