A trolley moves at constant velocity 3 m/s on a smooth horizontal surface. If sand is dropped perpendicularly on the trolley at the rate of 80 kg per
minute, what is the horizontal force required to mantain the movement of
the trolley at constant velocity 3 m/s?

Electroplating is a way to coat a complex metal object with a very thin (and hence inexpensive) layer of a precious metal, such as silver or gold. in essence the metal object is made the cathode of an electrolytic cell in which the precious metal cations are dissolved in aqueous solution. suppose a current of 480.ma is passed through an electroplating cell with an aqueous solution of agno3 in the cathode compartment for 46.0 seconds. calculate the mass of pure silver deposited on a metal object made into the cathode of the cell. round your answer to 3 significant digits. also, be sure your answer contains a unit symbol. ×10μ

Three charge are arranged as shown in the diagram. the magnitude of the net electrical force acting on the +6 uc charge, rounded to the tenths place, is .

Why does lightning travel from clouds to the ground?