A light spring obeys Hooke's law. The spring's unstretched length is33.5cm. One end of the spring is attached to the top of a doorframe and a weight with mass7.75kgis hung from the other end. The final length of the spring is40.0cm.

a)Find its spring constant (in N/m).

= 1168

b)The weight and the spring are taken down. Two people pull in opposite directions on the ends of the spring, each with a force of140N.Find the length (in m) of the spring in this situation.

c)What If?What would be the length (in m) of the spring if it were now attached to the vertical portion of the doorframe and stretched horizontally by a single person exerting a force of140N?