ALWAYS use significant figure rules. Remember that these rules apply to all numbers that are measurements. In working this problem, assume the value of "g" to be 9.8 m/s2 with two (2) significant digits unless otherwise stated.
A pulley system lifts a 500-lb block 1.0 foot with an effort of only 50 lb. If the 50 lb moves 30 feet, calculate the efficiency of the pulley system.

33 %
30. %
67 %
70. %

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

J. j. thomson’s experiment disproved the theory that an atom

As the distance from a magnet increases, what happens to the magnet force?