A longitudinal wave is observed to be moving along a slinky. Adjacent crests are 2.4 m apart. Exactly 6 crests are observed
to move past a given point in 9.1 s. Its wavelength is 2.4 m.
What is the frequency?

Acapacitor is storing energy of 3 joules with a voltage of 50 volts across its terminals. a second identical capacitor of the same value is storing energy of 1 joule. what is the voltage across the terminals of the second capacitor?