Avertical spring has a spring constant of
100. newtons per meter. when an object is
attached to the bottom of the spring, the spring
changes from its unstretched length of 0.50 meter
to a length of 0.65 meter. the magnitude of the
weight of the attached object is
(1) 1.1 n (3) 50. n
(2) 15 n (4) 65 n

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?