The tension t in a spring varies directly with the distance d the spring is stretched. If the tension is 42 pounds when the spring is stretched 2 inches, find the tension when the spring is stretched three times as far.
A)The tension is 138 pounds.
B)The tension is 126 pounds.
C)The tension is 121 pounds.
D)The tension is 118 pounds.
E)The tension is 252 pounds.

Question

Quizplus · Accepted Answer

Since the tension varies directly with the distance, we can use the formula T=k*d, where k is the constant of proportionality. To find k, we can use the given values:
42 = k*2
k = 21
Now we can use this value of k to find the tension when the spring is stretched three times as far:
T = 21*(3*2)
T = 126
Therefore, the tension is 126 pounds.

The Tension T in a Spring Varies Directly with the Distance