An ideal spring stretches by 21.0 cm when a 135-N object is hung from it. If instead you hang a fish from this spring, what is the weight of a fish that would stretch the spring by 31.0 cm?
A) 199 N
B) 145 N
C) 91 N
D) 279 N

Question

An ideal spring stretches by  21.0 cm when a 135-N object is hung from it. If instead you hang a fish from this spring, what is the weight of a fish that would stretch the spring by  31.0 cm?
A)  199 N
B)  145 N
C)  91 N
D)  279 N

Quizplus · Accepted Answer

The spring's stretch is directly proportional to the force applied (Hooke's Law). The ratio of force to stretch for the initial condition is 135 N / 21.0 cm. For the fish, the stretch is 31.0 cm, so the weight (force) of the fish can be found by setting up the proportion 135 N / 21.0 cm = x / 31.0 cm, solving for x gives 199 N.

An Ideal Spring Stretches by 21