Elastic Length Force
1. **Stating the problem:**
We have an elastic band initially 20 cm long. Each increase in force by 1 newton increases the length by 0.125 cm. We want to:
A) Find the equation relating length to force and provide a graph.
B) Find the force at which the band snaps at length 27.6 cm.
2. **Formula and explanation:**
The relationship between length $L$ and force $F$ is linear because the length increases steadily with force. This fits the form:
$$L = mF + c$$
where $m$ is the rate of increase in length per unit force, and $c$ is the initial length when force is zero.
3. **Finding $m$ and $c$:**
- Initial length $c = 20$ cm (when $F=0$).
- Increase in length per newton $m = 0.125$ cm/N.
So the equation is:
$$L = 0.125F + 20$$
4. **Graph:**
The graph is a straight line with slope 0.125 and y-intercept 20, showing length $L$ on the vertical axis and force $F$ on the horizontal axis.
5. **Finding the snapping force:**
Given the band snaps at length $L = 27.6$ cm, substitute into the equation:
$$27.6 = 0.125F + 20$$
Subtract 20 from both sides:
$$27.6 - 20 = 0.125F$$
$$7.6 = 0.125F$$
Divide both sides by 0.125:
$$F = \frac{7.6}{0.125} = 60.8$$
So, the band snaps when the force reaches 60.8 newtons.
**Final answers:**
- Equation relating length to force: $$L = 0.125F + 20$$
- Snapping force: $$F = 60.8$$ newtons