Two identical springs with spring constant 50 N/m support a 5.0-N weight as in the picture below. What is the tension in spring A?
A)1.45 N
B)2.50 N
C)2.89 N
D)3.75 N
E)5.00 N

Question

Two identical springs with spring constant 50 N/m support a 5.0-N weight as in the picture below. What is the tension in spring A? ​  ​
A)1.45 N 
B)2.50 N 
C)2.89 N 
D)3.75 N 
E)5.00 N

Quizplus · Accepted Answer

The force of the weight is split evenly between the two springs, so each spring has a force of 2.5 N acting on it. Using Hooke's Law, we can calculate the stretching of each spring: F = kx -> x = F/k. For each spring, x = 2.5 N / 50 N/m = 0.05 m. Since spring A is stretched by this amount and has a spring constant of 50 N/m, the tension in spring A is T = kx = 50 N/m * 0.05 m = 2.5 N. Therefore, the answer is choice C.

Two Identical Springs with Spring Constant 50 N/m Support a 5.0-N