Hooke's law describes a certain light spring of unstressed length 36.0 cm. When one end is attached to the top of a door frame and a 6.60 kg object is hung from the other end, the length of the spring is 41.50 cm.
(a) Find its spring constant.
(b) The load and the spring are taken down. Two people pull in opposite directions on the ends of the spring, each with a force of 190 N. Find the length of the spring in this situation.