Gravitational Orbits: True Statements about Circular & Elliptical Orbits

AI Thread Summary
In discussing gravitational orbits, key points include the characteristics of circular and elliptical orbits. For circular orbits, the planet's momentum is always tangent to its trajectory, its magnitude remains constant, and the gravitational force acts at a right angle to the momentum. In elliptical orbits, while the momentum is also tangent to the trajectory and its direction changes continuously, the magnitude of momentum is not constant due to varying speeds. The gravitational force similarly acts at a right angle to the momentum in both types of orbits. Understanding these principles is essential for grasping the dynamics of planetary motion.
Fredley_Banyo
Messages
6
Reaction score
0
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 missed this problem on my homework and i would like to know what the correct statements are for each so that i can understand the concepts.
 
Physics news on Phys.org
Welcome to PF, Fredley!
The purpose of the forum is to help you work out the answers yourself, so we are not supposed to just give you answers. If you share your thinking or work, we'll be very glad to point out any errors or omissions and aim you in the right direction.
 
I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
Thread 'A cylinder connected to a hanging mass'
Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
Back
Top