[Logarithms]Kepler's third law of planetary motion

In summary, Kepler's third law of planetary motion states that the period of a planet's orbit is related to its mean distance from the sun through the equation log P = \frac{1}{2} (log K + 3log R), where K is a constant. To rewrite this formula as a single logarithm, we can simplify it to log P = log K^\frac{1}{2} \cdot R^\frac{3}{2}. The answer in the textbook shows the equation being simplified to log(\frac{K^{\frac{1}{2}} \cdot R^{\frac{3}{2} }}P)=0, but it is unclear how they reached this conclusion.
  • #1
anonymous12
29
0

Homework Statement


Kepler's third law of planetary motion relates P, the period of a planet's orbit, to R, the planet's mean distance from the sun, through the equation [itex]log P = \frac{1}{2} (log K + 3log R)[/itex], where K is a constant.

Rewrite the formula as a single logarithm.

Homework Equations


[tex]log P = \frac{1}{2} (log K + 3log R)[/tex]

The Attempt at a Solution



Rewrite the formula as a single logarithm.
[tex]log P = \frac{1}{2} (log K + 3log R)[/tex]
[tex]log P = \frac{1}{2} (log(KR^3))[/tex]
[tex]log P = log K^\frac{1}{2} \cdot R^\frac{3}{2}[/tex]

I have no idea what to do next.

4. The answer in the back of the textbook
[tex]log(\frac{K^{\frac{1}{2}} \cdot R^{\frac{3}{2} }}P)=0[/tex]

Here I have no idea how they made the equation equal to 0. If anyone could help me I will be very grateful.
 
Physics news on Phys.org
  • #2
Nevermind. I got it!
 
  • #3
Glad we could help!
 

What is Kepler's third law of planetary motion?

Kepler's third law of planetary motion states that the square of the orbital period of a planet is directly proportional to the cube of its semi-major axis.

What does the semi-major axis refer to in Kepler's third law?

The semi-major axis is the longest radius of an elliptical orbit, which goes from the center of the ellipse to the furthest point on the orbit.

How did Kepler discover this law?

Johannes Kepler discovered this law by analyzing extensive data collected by Tycho Brahe on the motion of planets, specifically Mars.

What are the units for measuring the orbital period and semi-major axis in Kepler's third law?

The orbital period is measured in years and the semi-major axis is measured in astronomical units (AU).

Can Kepler's third law be applied to all planets?

Yes, Kepler's third law applies to all planets, as long as their orbits are elliptical and not too close to each other.

Similar threads

Replies
4
Views
753
  • Art, Music, History, and Linguistics
Replies
1
Views
1K
  • Calculus and Beyond Homework Help
Replies
1
Views
668
  • Precalculus Mathematics Homework Help
2
Replies
38
Views
5K
  • Precalculus Mathematics Homework Help
Replies
12
Views
2K
  • Precalculus Mathematics Homework Help
Replies
4
Views
2K
Replies
18
Views
1K
  • Set Theory, Logic, Probability, Statistics
Replies
8
Views
1K
  • Precalculus Mathematics Homework Help
Replies
8
Views
1K
  • Precalculus Mathematics Homework Help
Replies
12
Views
7K
Back
Top