Chapter 5: Problem 19
If it takes \(400 \mathrm{~J}\) of work to stretch a spring \(8.00 \mathrm{~cm}\) what is the spring constant?
Short Answer
Expert verified
The spring constant is approximately 125000 N/m.
Step by step solution
01
Understanding Hooke's Law
Hooke's Law describes the behavior of springs, stating that the force needed to stretch or compress a spring is proportional to the distance it is stretched or compressed. This is expressed with the formula:\[ W = \frac{1}{2} k x^2 \]where \(W\) is the work done, \(k\) is the spring constant, and \(x\) is the displacement of the spring.
02
Plugging in Given Values
We're given that the work \(W = 400 \text{ J}\), and the displacement \(x = 8.00 \text{ cm} = 0.08 \text{ m}\) (since we always convert to meters in SI units). The formula to find \(k\) becomes:\[ 400 = \frac{1}{2} k (0.08)^2 \]
03
Solving for the Spring Constant
Now we will rearrange the formula to solve for \(k\). First, simplify the equation:\[ 400 = \frac{1}{2} k (0.0064) \]Multiply both sides by 2 to clear the fraction:\[ 800 = k (0.0064) \]Finally, divide both sides by 0.0064 to solve for \(k\):\[ k = \frac{800}{0.0064} \approx 125000 \, \text{N/m} \]
04
Conclusion
After calculating, we find that the spring constant \(k\) is approximately \(125000 \text{ N/m}\). This value reflects how stiff or resistant to stretching the spring is.
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Spring Constant
The spring constant, denoted as \( k \), is a measure of a spring's stiffness. It tells us how much force is needed to stretch or compress the spring by a certain amount. Think of it as the difficulty level in changing the length of the spring. A higher spring constant means the spring is stiffer, making it harder to stretch. In our example, the spring constant was calculated to be \( 125000 \, \text{N/m} \). This value is obtained using Hooke's Law, which mathematically expresses this concept as \( W = \frac{1}{2} k x^2 \). From this formula, \( k \) can be isolated and calculated if the work \( W \) and displacement \( x \) are known.
When dealing with springs, always remember:
When dealing with springs, always remember:
- Higher \( k \): Stiffer spring
- Lower \( k \): Softer spring
- Always express displacement in meters for accuracy
Work and Energy
Work and energy are key concepts when analyzing springs. Work, in physics, is the amount of energy transferred by a force through a distance. In our exercise, it took \( 400 \, \text{J} \) (joules) of work to stretch the spring.
This means energy from an external force was applied to change the spring's length. The formula \( W = \frac{1}{2} k x^2 \) links work done on the spring to its displacement and spring constant. This equation shows that:
This means energy from an external force was applied to change the spring's length. The formula \( W = \frac{1}{2} k x^2 \) links work done on the spring to its displacement and spring constant. This equation shows that:
- More work equals more stretch
- Stiffer springs require more work for the same stretch
- Energy is stored in the spring, a concept known as potential energy
Displacement
Displacement in the context of Hooke’s Law is the change in length of a spring when a force is applied. In our scenario, the spring was stretched by \( 8.00 \, \text{cm} \), which converts to \( 0.08 \, \text{m} \). Always remember to convert any measurements to meters in physics for consistency with SI units.
Displacement is a pivotal factor in Hooke's Law, as it directly affects how much work is done on the spring. The relationship can be observed in:
Displacement is a pivotal factor in Hooke's Law, as it directly affects how much work is done on the spring. The relationship can be observed in:
- Small displacement = less work
- Large displacement = more work
- The displacement squared factor indicates non-linear impact on energy needed