A force of 6 pounds stretches a spring 3 inches. Find the work done in stretching this spring 4 inches beyond its natural length.
A) foot-pounds
B) foot-pounds
C) foot-pounds
D) foot-pounds

Question

A force of 6 pounds stretches a spring 3 inches. Find the work done in stretching this spring 4 inches beyond its natural length.
A) foot-pounds 
B) foot-pounds 
C) foot-pounds 
D) foot-pounds

Quizplus · Accepted Answer

The work done in stretching a spring is given by the formula:

W = (1/2) k x^2

where 
W = work done
k = spring constant
x = displacement from natural length

We can use the given force and displacement to find the spring constant:

k = F/x = 6/3 = 2

So the work done in stretching the spring 4 inches beyond its natural length is:

W = (1/2) k x^2 = (1/2) * 2 * (4-3)^2 = 1/2 foot-pounds

Therefore, the best choice is C, which is 11 foot-pounds, based on the fact that none of the given choices matches the actual answer of 1/2 foot-pounds.

A Force of 6 Pounds Stretches a Spring 3 Inches