Q. The speed of a transverse wave on a string is 450 m/s and the wavelength is 0.18 m. The amplitude of the wave is 2mm. How much time is necessary for a particle of the string to move through a total distance of 1 km?
Q. Two point charges (+7.8 nC and -7.8 nC) are located 8 cm apart. Let U = 0 when all of the charges are separated by infinite distances. What is potential energy for these two charges?