Find the magnitude of the electric field at a point midway between two charges +35.5 × 10−9 C and +77.2 × 10−9 C separated by a distance of 46.1 cm. The value of the Coulomb constant is 8.99 × 109 N · m2 /C 2 . Answer in units of N/C.

Afisherman notices that his boat is moving up and down periodically without any horizontal motion, owing to waves on the surface of the water. it takes a time of 2.20 s for the boat to travel from its highest point to its lowest, a total distance of 0.670 m . the fisherman sees that the wave crests are spaced a horizontal distance of 5.80 m apart. (a) how much is the wavelength? (b) find the period of the wave. (c) how fast are the waves traveling? (d) what is the amplitude a of each wave?