In each case, a charged rod, made of the dense rubber ebonite, comes close or is in contact with the top of an electroscope. The ball on top of the electroscope is directly connected to the two metal leaves suspended in the flask.

Which image represents a gaining of a charge on the leaves of the electroscope by conduction?

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?