why not B (1 Viewer)

[kkk579]

centripetal acceleration is always towards the centre of the motion and clearly B is pointing towards the centre so why is it A? or does this only apply to perfectly circular orbits cos this one is more of an ellipse

 

[C2H6O]

You are correct that the force should point to the centre in uniform circular motion. But consider where this force would be coming from in the scenario of B. It cannot come from nowhere. The only force that makes sense here is gravity, which would act toward the centre of Earth. It's kinda a trick question, cause its not actually ucm, the sattelite would eventually fall out of the path shown (I think).

 

[kkk579]

You are correct that the force should point to the centre in uniform circular motion. But consider where this force would be coming from in the scenario of B. It cannot come from nowhere. The only force that makes sense here is gravity, which would act toward the centre of Earth. It's kinda a trick question, cause its not actually ucm, the sattelite would eventually fall out of the path shown (I think).

Why would it fall out of the path? That only happens when its velocity decreases

 

[C2H6O]

Why would it fall out of the path? That only happens when its velocity decreases

Cause the force is not acting in the way that will keep it in ucm, and consequently uniform velocity. Velocity will only be maintained if the force acts to the centre. Of course I could be wrong but it doesn’t really matter for this question.

 

[C2H6O]

Someone correct me if I’m wrong

 

[kkk579]

Cause the force is not acting in the way that will keep it in ucm, and consequently uniform velocity. Velocity will only be maintained if the force acts to the centre. Of course I could be wrong but it doesn’t really matter for this question.

Tbh idk what ur tryna say but i js searched it up and its says for an object orbitting another object in an ellipse motion the acceleration doesnt act towards the centre of the ellipse but rather the object its orbitting

 

[Average Boreduser]

Tbh idk what ur tryna say but i js searched it up and its says for an object orbitting another object in an ellipse motion the acceleration doesnt act towards the centre of the ellipse but rather the object its orbitting

um girlie , its not in ucm. The net ACCELERATION is the gravitational force. since its not in circular motion, the acceleration is from the force (generally net here since no other forces acting on the satellite) from the planet.

 

[kkk579]

um girlie , its not in ucm. The net ACCELERATION is the gravitational force. since its not in circular motion, the acceleration is from the force (generally net here since no other forces acting on the satellite) from the planet.

Yeah but its not circular motion either so acceleration wouldnt be towards the middle but towards the mass its orbiting

 

[Average Boreduser]

Yeah but its not circular motion either so acceleration wouldnt be towards the middle but towards the mass its orbiting

yea... hence A right?

 

[kkk579]

yea... hence A right?

Yeah i just didnt originally know that if the object doesnt orbit the central mass in a perfect circle then acceleration doesnt necessarily act towards the centre

 

[wizzkids]

It is not uniform circular motion (UCM). The orbit of the satellite is an ellipse. An ellipse is a stable orbit. The object is not going to crash.
The force that keeps the two objects gravitationally bound together is the gravitational attraction vector that always points towards the centre of mass of each object. The correct answer is (A).
In general all objects in orbit usually have elliptical orbits. It is very rare to find a perfectly circular orbit, but the NSW Physics syllabus says we can discuss elliptical orbits only in a qualitative sense, not quantitatively.