Plan for Today (AP Physics 1) Class Review

Know and be able to apply Hooke’s Law F = -kx Force = spring constant * displacement Negative means that the force opposes (opposite direction) of the displacement Be able to solve for each part

Equations of motion for simple harmonic oscillators V and a as a function of x, and x and v as a function of t Remember: for function of t, mode MUST be in radians to work

Periodic of a SHM Spring mass system Pendulum Equation: Pendulum Be able to solve for various parts

Describe the parts of longitudinal and transverse waves Vibration parallel to motion Has compressions (close together) and rarefactions (far apart) Transverse Vibration perpendicular to motion Crests (high part) and troughs (low part) Around equilibrium position (halfway between crest and trough) Wavelength – from crest to crest/trough to trough

Damped Harmonic Motion Big idea – gets less and less (because of friction/real life variables) - but for whatever is in harmonic motion, the period should stay the same

Speed of Waves on a String V = wave length * frequency V = wavelength/period

Superposition and Interference Superposition – when waves are coming together Interference Constructive – same phase, get bigger Destructive – opposite phase, subtract Can be complete if they are exactly the same

1. Hooke’s Law Example Problem A rubber band stretches 5 cm when a 15 g mass is attached to it. What is the spring constant of the rubber band? How far would the rubber band stretch if a 50 g mass was attached?

2. Example problem for equations of simple harmonic oscillation An object is in simple harmonic motion according to the following equation (assume distances are in m) X = 4 * cos (3 * pi * t) What is the amplitude? What is the period of the motion? Write the equation for the acceleration of the system What is the object’s displacement at t = 1.2 s?

3. Example Problem for Period of SHM A spring mass system has a mass of 1.5 kg and a spring constant of 53 N/m. The maximum displacement is 25 cm. Find The period The frequency The velocity at 12 cm from equilibrium

4. Example Problem Sketch a period of

5. Example with Longitudinal and Transverse Waves Compare and contrast longitudinal and transverse waves

6. Example Problem for Speed of Waves A rope is 10 m long and has a mass of 0.5 kg. A wave on it has a velocity of 8 m/s. What is the tension of the rope?

7. Example Problem with Superposition and Interference Sketch examples of constructive interference and complete destructive interference before, during, and after the waves meet

Answer to 1 K = 2.94 N/m X = .17 m or about 17 cm

2. Answer A = 4 m T = .67 s (f = 1.5 Hz) a = - 4 * (3 pi)^2 * cos (3 * pi * t) X = 1.23 m

3. Answers T = 1.06 s f = .95 Hz V = 1.3 m/s

4. Answer

5. Answer Longitudinal waves – particle motion is parallel to the motion of the wave, consists of compressions and rarefactions Sound waves Transverse waves – particle motion is perpendicular to the wave motion, typical sine wave look Light waves

6. Answer 3.2 N

7. Answer Constructive Interference

7. Answer Complete destructive interference