- #1
Fredley_Banyo
- 6
- 0
Homework Statement
1. Which of the following statements about a circular orbit are true? (The planet is orbiting around the star.)
a. At any instant the momentum of the planet is tangent to the planet's trajectory.
b. The magnitude of the planet's momentum is constant.
c. At every instant, dvector p/dt points from the planet to the star.
d. The direction of the planet's momentum is changing at every instant.
e.The gravitational force on the planet due to the star always acts at a right angle to the planet's momentum.
2. Which of the following statements about an elliptical orbit are true? (The planet is orbiting around the star.)
a. At any instant the momentum of the planet is tangent to the planet's trajectory.
b. The magnitude of the planet's momentum is constant.
c. At every instant, dvector p/dt points from the planet to the star.
d. The direction of the planet's momentum is changing at every instant.
e.The gravitational force on the planet due to the star always acts at a right angle to the planet's momentum.
I want to know which choice applies to each so i can better understand the concepts of gravitational orbits.
The Attempt at a Solution
My guess for a circular orbit was a,b,d and e because the momentum's magnitude is constant but is constantly changing direction. The gravitational force from the star is pointed towards the center of the orbit so that is why i thought e was true as well. As for an elliptical orbit i really have to idea except for the fact that the magnitude of momentum is not constant which makes it elliptical and not circular.