The length, l, that a spring is stretched varies directly as the amount of force, F, applied to the end of the spring. When a force of 10 pounds is applied to a spring, it stretches 3 inches. How much will the same spring stretch if the force is increased to 15 pounds? A.
8 inches
B.
7.5 inches
C.
4.5 inches
D.
2 inches

C. 4.5 inches

Step-by-step explanation:

Given the following data;

Force, F = 10 pounds

Extension, e = 3 inches

First of all, we would determine the spring constant (k) using the following formula;

Force = spring constant * extension

10 = spring constant * 3

Spring constant = 10/3

Spring constant = 3.33 pounds per inches.

Next, we would find the extension of the spring when a force of 15 pounds is applied;

F = ke

15 = 3.33 * e

Extension, e = 15/3.33

Extension, e = 4.5 inches.