Question: 3. [9 pts.] We can use Newton's Law of Gravity to measure the gravitational attraction between the moon and a PreCalculus student in a space ship located a distance from the moon's surface: $F(x) = \frac{350}{x^2}$. Here $F$ is measured in newtons (N), and $x$ is measured in millions of meters.
A. Graph the function $F$ for values of $x$ between 0 and 10.
B. Use the graph to describe the behavior of the gravitational attraction $F$ as the distance $x$ increases.
C. Determine the average rate of change in $F(x)$ from $x=1$ to $x = h$, with $h > 1$. Fully reduce all fractions, no fractions should be left in a fraction.
1. **State the problem:**
We are given the gravitational attraction function $$F(x) = \frac{350}{x^2}$$ where $F$ is in newtons and $x$ is the distance in millions of meters from the moon's surface.
2. **Part A: Graph the function $F(x)$ for $x$ between 0 and 10.**
The function is a rational function with a vertical asymptote at $x=0$ and decreases as $x$ increases.
3. **Part B: Describe the behavior of $F$ as $x$ increases.**
As $x$ increases, since $F(x) = \frac{350}{x^2}$, the denominator grows larger, so $F(x)$ decreases rapidly towards zero. This means the gravitational attraction weakens as the distance increases.
4. **Part C: Find the average rate of change of $F(x)$ from $x=1$ to $x=h$, where $h>1$.**
The average rate of change formula is:
$$\text{Average rate of change} = \frac{F(h) - F(1)}{h - 1}$$
Calculate $F(1)$ and $F(h)$:
$$F(1) = \frac{350}{1^2} = 350$$
$$F(h) = \frac{350}{h^2}$$
Substitute into the formula:
$$\frac{\frac{350}{h^2} - 350}{h - 1} = \frac{350\left(\frac{1}{h^2} - 1\right)}{h - 1} = \frac{350\left(\frac{1 - h^2}{h^2}\right)}{h - 1} = \frac{350(1 - h^2)}{h^2(h - 1)}$$
Factor numerator $1 - h^2$ as $(1 - h)(1 + h)$:
$$\frac{350(1 - h)(1 + h)}{h^2(h - 1)}$$
Note that $1 - h = -(h - 1)$, so:
$$\frac{350 \cdot -(h - 1)(1 + h)}{h^2(h - 1)} = \frac{-350 (h - 1)(1 + h)}{h^2 (h - 1)}$$
Cancel $(h - 1)$:
$$\frac{-350 \cancel{(h - 1)} (1 + h)}{h^2 \cancel{(h - 1)}} = \frac{-350 (1 + h)}{h^2}$$
5. **Final answer:**
The average rate of change of $F(x)$ from $x=1$ to $x=h$ is:
$$\boxed{\frac{-350(1 + h)}{h^2}}$$
This shows the rate at which the gravitational force changes with distance between $1$ and $h$ million meters.