A spring that has a spring constant of [tex]$1400 \, N/m$[/tex] is stretched to a length of 2.5 m. If the natural length of the spring is 1.0 m, how much elastic potential energy is stored in the spring?

A. 700 J
B. 1050 J
C. 1575 J
D. 4375 J



Answer :

Sure! Let's solve the problem step-by-step:

1. Identify the given information:
- Spring constant ([tex]\(k\)[/tex]): 1400 N/m
- Stretched length of the spring ([tex]\(L_s\)[/tex]): 2.5 m
- Original (unstretched) length of the spring ([tex]\(L_o\)[/tex]): 1.0 m

2. Calculate the deformation (stretch) of the spring:
The deformation ([tex]\(x\)[/tex]) is the difference between the stretched length and the original length:
[tex]\[ x = L_s - L_o \][/tex]

Given:
[tex]\[ L_s = 2.5 \, \text{m} \][/tex]
[tex]\[ L_o = 1.0 \\, \text{m} \][/tex]

Substitute these values:
[tex]\[ x = 2.5 \, \text{m} - 1.0 \, \text{m} \][/tex]
[tex]\[ x = 1.5 \, \text{m} \][/tex]

3. Calculate the elastic potential energy stored in the spring:
The formula to calculate elastic potential energy ([tex]\(E\)[/tex]) stored in a spring is:
[tex]\[ E = \frac{1}{2} k x^2 \][/tex]

Here:
- [tex]\(k\)[/tex] is the spring constant (1400 N/m)
- [tex]\(x\)[/tex] is the deformation (1.5 m)

Substitute the values into the formula:
[tex]\[ E = \frac{1}{2} \times 1400 \, \frac{\text{N}}{\text{m}} \times (1.5 \, \text{m})^2 \][/tex]
[tex]\[ E = \frac{1}{2} \times 1400 \times 2.25 \][/tex]
[tex]\[ E = \frac{1}{2} \times 3150 \][/tex]
[tex]\[ E = 1575 \, \text{J} \][/tex]

4. Conclusion:
The elastic potential energy stored in the spring when it is stretched to a length of 2.5 m is 1575 J.

Therefore, the correct answer is:
[tex]\[ \text{1575 J} \][/tex]