PHYS16 – Lecture 32 Simple Harmonic Motion November 29, 2010

Exam Answers

Question 1 – Lift of Plane Use Bernoulli to calculate lift Use Newton’s laws

Question 2 – Height of sky and ocean Height of sky given constant density Height of sky given that density changes Height of ocean given constant density

Question 3 – Car performance Power of car Torque of car (4 wheels)

Question 3 – Car performance Rpm of engine Torque on wheels

Question 4 – Answer is 42 Time for ball to tunnel through Earth Distance to geostationary orbit

Question 4 – Answer is 42 Time for low orbit satellite to go ½ around Earth Height of object on Ganymede

Question 5 – Swing set John jumps on Merry-go-round Balancing multiperson see-saw

Question 5 – Swing set Mass of kid on tippy bridge

Outline for Oscillations Simple Harmonic Motion – Position, Velocity, Acceleration – Force – Energy Waves – Mechanical waves – Intensity and Power – Superposition and Interference – Standing Waves

Simple Harmonic Motion: Position, Velocity, Acceleration

Oscillations and Periodic Motion

Simple Harmonic Motion Equilibrium Point 1) About Equilibrium 2) Periodic 3) Sinusoidal

Examples Mass on a Spring Pendulum Snowboarder in halfpipe Bungee jumper Child on swing Bobble head doll?

SHM Position, Velocity, Acceleration

Example Question What is the max speed and when does it occur? Equilibrium Point

Example Question An object undergoes simple harmonic motion. If the amplitude and period are doubled, the object’s max speed is: A)Quadrupled B)Doubled C)Unchanged D)Halved E)Quartered

Simple Harmonic Motion: Restoring Force

Restoring Force Force that always points back to the equilibrium position k is just a constant – for a spring it is the spring constant

SHM – Restoring Force

Example Question A block on a spring has a period of T. What is the period if: A)the mass is doubled? B)k is quadrupled? C)A is doubled?

Example Question What is the period of a pendulum?

Simple Harmonic Motion: Energy

Energy in SHM

Main Points - SHM Movement Restoring Force creates oscillation Energy is dependent on amplitude