Question

To store stacks of clean plates, a cafeteria uses a closed cart with a spring-loaded shelf inside. Customers can take plates off the stack one at a time through a hole in the top. A stack of plates compresses the spring 0.40 m. The spring constant is 240 N/m. What is the elastic potential energy of the spring? *
A) 20 J
B) 48 J
C) 96 J
D) 240 J

Answer 1

The answer for the following problem is mentioned below.

The option for the question is "A" approximately.

• Therefore the elastic potential energy of the string is 20 J.

Explanation:

Given:

Spring constant (k) = 240 N/m

amount of the compression (x) = 0.40 m

To calculate:

Elastic potential energy (E)

We know;

According to the formula;

    E = $\frac{1}{2}$ × k × x × x

   E = $\frac{1}{2}$ × k ×(x)²

where;

E represents the elastic potential energy

K represents the spring constant

x represents amount of the compression in the string

So therefore,

Substituting the values in the above formula;

      E = $\frac{1}{2}$ × 240 × (0.40)²

      E =  $\frac{1}{2}$ × 240 × 0.16

      E =  $\frac{1}{2}$ × 38.4

      E = 19.2 J or approximately 20 J

Therefore the elastic potential energy of the string is 20 J.