Let's analyze both
Data Set 5 and
Data Set 6, determine the mathematical relationships between the variables, and then write the corresponding
mathematical expressions.
---
🔹 Data Set 5
| R (a.u.) | T (yr) |
|---------|--------|
| 0.38 | 0.24 |
| 0.72 | 0.62 |
| 1.00 | 1.00 |
| 1.52 | 1.88 |
| 5.19 | 11.9 |
| 9.53 | 29.5 |
| 19.1 | 84.1 |
| 30.0 | 165 |
| 39.4 | 249 |
We are to find a relationship between
R (distance in astronomical units) and
T (orbital period in years).
This resembles
Kepler’s Third Law, which states:
> $ T^2 \propto R^3 $
Or more precisely:
> $ T^2 = k \cdot R^3 $
Let’s test this by calculating $ T^2 $ and $ R^3 $ for a few values.
#### Try: $ T^2 / R^3 $
For each row, compute $ \frac{T^2}{R^3} $:
1. $ R = 0.38, T = 0.24 $
- $ T^2 = 0.0576 $
- $ R^3 = 0.054872 $
- $ T^2/R^3 ≈ 1.053 $
2. $ R = 0.72, T = 0.62 $
- $ T^2 = 0.3844 $
- $ R^3 = 0.373248 $
- $ T^2/R^3 ≈ 1.029 $
3. $ R = 1.00, T = 1.00 $
- $ T^2 = 1 $
- $ R^3 = 1 $
- $ T^2/R^3 = 1 $
4. $ R = 1.52, T = 1.88 $
- $ T^2 = 3.5344 $
- $ R^3 = 3.511808 $
- $ T^2/R^3 ≈ 1.006 $
5. $ R = 5.19, T = 11.9 $
- $ T^2 = 141.61 $
- $ R^3 ≈ 140.1 $
- $ T^2/R^3 ≈ 1.01 $
All values of $ T^2/R^3 $ are approximately
1, with small variations due to rounding.
✔ So, the relationship is:
> $ T^2 = R^3 $
Or:
> $ T = R^{3/2} $
---
✔ Mathematical Expression #5
$$
\boxed{T = R^{3/2}}
$$
This is
Kepler's Third Law for objects orbiting the Sun (in AU and years). It shows that the square of the orbital period is proportional to the cube of the semi-major axis.
---
🔹 Data Set 6
| r (m) | F_g (N) |
|-------|--------|
| 0.2 | 425 |
| 0.5 | 68.3 |
| 1.0 | 16.5 |
| 2.0 | 4.26 |
| 5.0 | 0.67 |
| 10.0 | 0.18 |
| 20.0 | 0.042 |
We are to find the relationship between
r (distance in meters) and
F_g (gravitational force in Newtons).
This looks like
inverse square law, such as Newton’s Law of Gravitation:
> $ F \propto \frac{1}{r^2} $
Let’s test this by computing $ F_g \cdot r^2 $ — if it's constant, then $ F_g \propto 1/r^2 $
Compute $ F_g \cdot r^2 $ for each row:
1. $ r = 0.2 $, $ F = 425 $
- $ r^2 = 0.04 $
- $ F \cdot r^2 = 425 × 0.04 = 17 $
2. $ r = 0.5 $, $ F = 68.3 $
- $ r^2 = 0.25 $
- $ F \cdot r^2 = 68.3 × 0.25 = 17.075 $
3. $ r = 1.0 $, $ F = 16.5 $
- $ r^2 = 1 $
- $ F \cdot r^2 = 16.5 $
4. $ r = 2.0 $, $ F = 4.26 $
- $ r^2 = 4 $
- $ F \cdot r^2 = 4.26 × 4 = 17.04 $
5. $ r = 5.0 $, $ F = 0.67 $
- $ r^2 = 25 $
- $ F \cdot r^2 = 0.67 × 25 = 16.75 $
6. $ r = 10.0 $, $ F = 0.18 $
- $ r^2 = 100 $
- $ F \cdot r^2 = 0.18 × 100 = 18 $
7. $ r = 20.0 $, $ F = 0.042 $
- $ r^2 = 400 $
- $ F \cdot r^2 = 0.042 × 400 = 16.8 $
Values are all around
17, with minor variation due to rounding or measurement error.
So, we can say:
> $ F_g \cdot r^2 \approx 17 $
Thus,
> $ F_g = \frac{17}{r^2} $
---
✔ Mathematical Expression #6
$$
\boxed{F_g = \frac{17}{r^2}}
$$
This matches the inverse-square law for gravitational force, where the constant 17 depends on the masses involved and the gravitational constant.
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📌 Final Answers:
####
Mathematical Expression #5:
$$
\boxed{T = R^{3/2}}
$$
####
Mathematical Expression #6:
$$
\boxed{F_g = \frac{17}{r^2}}
$$
These are the best-fit mathematical models based on the data provided.
Let me know if you'd like graphs or further analysis!
Parent Tip: Review the logic above to help your child master the concept of unit 1 worksheet 1 graphing practice.