A vertical 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