Question

The amount a spring will stretch varies directly with the amount of weight attached to the spring. If a spring stretches 2.1 inches when 80 pounds is attached, how far will it stretch when 40 pounds is attached?

Answer 1

A. 1.05 in.

Explanation:

Answer 2

`1.05\ in`

Explanation:

we know that

A relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form
`y/x=k` or
`y=kx`

Let

x -----> the amount of weight

y ----- the amount a spring will stretch

we know that

For x=80 lb, y=2.1 in

Find the value of k (constant of proportionality)

`k=y/x`

substitute the values

`k=2.1/80`

The linear equation is

`y=(2.1/80)x`

How far will it stretch when 40 pounds is attached?

For x=40 lb

substitute the value of x in the linear equation and solve for y

`y=(2.1/80)(40)=1.05\ in`