Two pure tones are sounded together. The drawing shows the pressure variations of the two sound waves, measured with respect to atmospheric pressure, where t1 = 0.0220 s and t2 = 0.0242 s. What is the beat frequency?

The protons in a nucleus are approximately 2 ✕ 10^−15 m apart. consider the case where the protons are a distance d = 1.93 ✕ 10^−15 m apart. calculate the magnitude of the electric force (in n) between two protons at this distance.