Four point charges of equal magnitude but different signs are arranged on the corners of a square as shown above. Which of the vectors shown represents the direction of the net force acting on the charge in the upper left-hand corner of the square, due to the other charges?

Aswimming pool whose volume is 10 comma 000 gal contains water that is 0.01% chlorine. starting at tequals0, city water containing 0.003% chlorine is pumped into the pool at a rate of 5 gal/min. the pool water flows out at the same rate. what is the percentage of chlorine in the pool after 1 hour? when will the pool water be 0.006% chlorine?