Calculate Period of Planet X with Kepler's Third Law

In summary, Kepler's third law states that the square of a planet's orbital period is directly proportional to the cube of its semi-major axis. Using this law, the formula for the period of planet X (TX) with an orbital radius (RX) twice that of Earth (RE) is TX = (1 Year) x (RX/RE)^3, or alternatively, TX^2 = (1 Year) x (RX/RE)^3.
  • #1
meemosewa
9
0
Using Kepler's Third Law, give the formula for the period TX of planet X whose orbital radius RX is twice that of earth, RE.

A. TX=(1 Year)x(RX/RE)^3
B. TX^2=(1 Year)x(RX/RE)^3
C. TX=(1 Year)x(RE/RX)^3
D. TX^2=(1 Year)x(RE/RX)^3

My book is not giving me a formula to use, so i a totally stuck... and ideas?
 
Physics news on Phys.org
  • #2
What does Kepler's third law say?
 
  • #3
thats part of the problem, i don't know what it says
 

Related to Calculate Period of Planet X with Kepler's Third Law

1. How do you calculate the period of a planet using Kepler's Third Law?

Kepler's Third Law states that the square of a planet's orbital period is directly proportional to the cube of its semi-major axis. This means that the period can be calculated by taking the square root of the distance of the planet from the sun cubed. The formula is P^2 = a^3, where P is the period and a is the semi-major axis in astronomical units (AU).

2. What is the semi-major axis and how is it measured?

The semi-major axis is the average distance between the planet and the sun. It is measured in astronomical units (AU), which is equivalent to the distance between the Earth and the sun. The semi-major axis can also be measured in kilometers or miles, but using AU is more convenient for astronomical calculations.

3. Can Kepler's Third Law be used for all planets?

Yes, Kepler's Third Law can be used for all planets in our solar system and also for exoplanets (planets outside of our solar system). However, it is most accurate for planets with circular or nearly circular orbits.

4. How do you convert the period of a planet from years to days?

To convert the period from years to days, you can use the following formula: P (days) = P (years) x 365.25. This takes into account the fact that a year is not exactly 365 days, but 365.25 days. For example, if the period of a planet is 2 years, the converted period in days would be 730.5 days.

5. Is there a way to calculate the period of a planet if its semi-major axis is unknown?

Yes, there is a way to calculate the period of a planet even if its semi-major axis is unknown. In this case, you can use the formula P^2 = (4π^2/G) x (a^3/M), where G is the gravitational constant and M is the mass of the sun. This formula is derived from Kepler's Third Law and can be used to calculate the period of a planet using the mass of the sun and the distance between the planet and the sun.

Similar threads

Find the location knowing the resonance using Kepler's third law
    • Introductory Physics Homework Help
Replies
2
Views
458
Kepler's Third Law vs Conservation of angular momentum
    • Introductory Physics Homework Help
Replies
8
Views
1K
Some homework questions in astrophysics (Kepler's Laws, Newton's Laws)
    • Introductory Physics Homework Help
Replies
6
Views
1K
Apparent (clearly false) contradiction - Kepler's Third Law
    • Introductory Physics Homework Help
Replies
2
Views
985
B Proof of inverse square law for gravitation?
    • Mechanics
Replies
18
Views
1K
Kepler's third law implies force proportional to mass
    • Introductory Physics Homework Help
Replies
10
Views
2K
I Kepler orbits for planets of similar masses
    • Classical Physics
Replies
2
Views
811
Kepler's Third Law and Motion of Two Point Masses
    • Introductory Physics Homework Help
Replies
8
Views
1K
What is the R^3 in Kepler's 3rd Law?
    • Introductory Physics Homework Help
Replies
7
Views
1K
Calculating Angular Diameter of an Orbit Using Kepler's Law
    • Introductory Physics Homework Help
Replies
4
Views
986

Hot Threads

Recent Insights

Back
Top