<aside> 💡 A wave is a moving disturbance that transports energy form one place to another but does not transport matter

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• The speed of a periodic wave is related to its wavelength and frequency by the universal wave equation, $v = f\lambda$
  • Frequency is equal to the reciprocal of time, $f=\frac{1}{t}$$t=\frac{1}{f}$
  • To find period, divide time given by one “rotation”
  • To find the period of a mass on a spring: $T =2\pi \sqrt{\frac{m}{k}}$
  • To find the period of a pendulum: $T = 2\pi \sqrt{\frac{L}{9.8m/s^2}}$
• For reflection, the angle between the incident ray and the normal to the reflecting surface is measured, as well as the angle between the reflected rat and the normal to the reflecting surface

The law of reflection states that the angle of incidence is equal to the angle of reflection as follows: $\theta_i = \theta_r$