An applied force of 20 N accelerates a block across a level, frictionless surface from rest to a velocity of 8.0 m/s in a time of 2.5 s. Calculate the work done by this force.

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?