# Finding quantity of energy stored in a spring

• Benzene_ring
In summary, the problem involves finding the amount of energy stored in a spring, with one part asking for the work required to stretch the spring from 0 to 20 cm and the other part asking for the exact quantity of energy stored when the spring is stretched 7.753 cm. The equation for elastic energy, Ee= 1/2kx^2, is used to solve the problem. It is important to convert all units to standard units (meters) before solving.
Benzene_ring

## Homework Statement

Hey guys, I'm having some trouble finding the exact quantity of energy storied in this spring problem.
It's like a problem with parts A and B, part A says "Determine the amount of work required to stretch the spring from 0 to 20 cm. I found that to be 125J. For Part B, it says "Suppose that this spring was stretched 7.753 cm. Find the exact quantity of energy stored in the spring.

## Homework Equations

I think that the equation that i would use is the one for elastic energy, Ee= 1/2kx^2

## The Attempt at a Solution

So far i have Ee= 1/2kx^2

Ee= 1/2k(7.753)^2
I'm not sure if I'm doing this right, or what to do next.

Thanks

How did you solve part A?

For part A, it had a diagram and the displacement was 20 cm and the force was 12.5N so i calculated 20*12.5/2= 125J

Benzene_ring said:
For part A, it had a diagram and the displacement was 20 cm and the force was 12.5N so i calculated 20*12.5/2= 125J
I assume that the 12.5 N force was the force required to stretch the spring 20 cm. So what's the spring constant?

Careful with units! (Convert distances to standard units: m, not cm.)

I divided 12.5 by 20 and got 0.625, but should i have converted before dividing?

Benzene_ring said:
I divided 12.5 by 20 and got 0.625, but should i have converted before dividing?
Yes. You want k in N/m, not N/cm.

Ok, i think i got the right answer.
Ee= 1/2 (625)(0.0078)^2
Ee= 1/2(625)(0.00006)
Ee= 0.01875J

Thank for all the help!

Benzene_ring said:
Ok, i think i got the right answer.
Ee= 1/2 (625)(0.0078)^2
Ee= 1/2(625)(0.00006)
Ee= 0.01875J
Careful! (But you're almost there.)

Check your values for k and for the amount of stretch.

## 1. What is the formula for finding the quantity of energy stored in a spring?

The formula for finding the quantity of energy stored in a spring is: E = 1/2 * k * x^2 where E is the energy stored, k is the spring constant, and x is the displacement of the spring from its equilibrium position.

## 2. How do you determine the spring constant of a spring?

The spring constant can be determined by dividing the force applied to the spring by the displacement caused by that force. This can be represented by the equation: k = F/x where k is the spring constant, F is the applied force, and x is the displacement of the spring.

## 3. What units are used to measure the quantity of energy stored in a spring?

The quantity of energy stored in a spring is typically measured in joules (J). However, it can also be measured in newton-meters (N*m) or kilogram-meters squared per second squared (kg*m^2/s^2).

## 4. Can the energy stored in a spring be negative?

Yes, the energy stored in a spring can be negative if the spring is compressed rather than stretched. This means that the spring is exerting a restorative force in the opposite direction of the applied force, resulting in a negative value for the energy stored.

## 5. How does the mass of an object affect the energy stored in a spring?

The mass of an object does not directly affect the energy stored in a spring. However, the energy stored can indirectly be affected by the mass of an object if it changes the displacement of the spring. A heavier object may cause a greater displacement, resulting in a greater energy stored in the spring.

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