Question

penny attaches a weight of 2.5 pounds to a spring, and it stretches 18 inches. how far will the spring stretch for a weight of 6.4 pounds, assuming the rate of stretch per unit of weight stays constant? a. 42.43 in b. 44.86 in c. 40.25 in d. 46.08 in

Explanation:

Step1: Find the stretch rate

The rate of stretch per unit weight is the stretch divided by the weight. So for 2.5 pounds and 18 inches, the rate $r = \frac{18}{2.5}$ inches per pound.
Calculating $\frac{18}{2.5}=7.2$ inches per pound.

Step2: Calculate stretch for 6.4 pounds

Using the rate, the stretch $s$ for 6.4 pounds is $s = r\times6.4$.
Substituting $r = 7.2$, we get $s = 7.2\times6.4 = 46.08$ inches.

Answer:

D. 46.08 in