Conceptual Question: Stars in intergalactic space with speed

In summary: Objects do not attract each other, they push each other away. So as the two stars move farther and farther apart, the force of their own gravity would cause them to move away from each other more and more quickly, until they finally stopped (due to the immense distance between them). This is what is happening in the problem, the speed is decreasing but at a much slower rate than if there weren't two stars in the first place.
  • #1
idllotsaroms
26
0

Homework Statement



http://postimage.org/image/7rgmo1527/
How is the speed decreasing and acceleration decreasing in this problem?

Homework Equations



Kepler's Laws?


The Attempt at a Solution



I remember in lecture my professor was saying something along the lines of objects attracting each other. So, since there are two stars that are maybe attracting each other, as they get farther and farther apart by a distance of r, shouldn't the speed increase--because the force of attraction (already negligible) is even smaller as they go farther apart? Does this question pertain to Newton's laws or Kepler's laws?

Thank you for your time!
 
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  • #2
idllotsaroms said:

Homework Statement



http://postimage.org/image/7rgmo1527/
How is the speed decreasing and acceleration decreasing in this problem?

Homework Equations



Kepler's Laws?

The Attempt at a Solution



I remember in lecture my professor was saying something along the lines of objects attracting each other. So, since there are two stars that are maybe attracting each other, as they get farther and farther apart by a distance of r, shouldn't the speed increase--because the force of attraction (already negligible) is even smaller as they go farther apart? Does this question pertain to Newton's laws or Kepler's laws?

Thank you for your time!
Do you know the difference between acceleration and speed?
 
  • #3
mm speed is a scalar and acceleration is vector? Acceleration of the rate of change of the speed.
 
  • #4
idllotsaroms said:
mm speed is a scalar and acceleration is vector? Acceleration of the rate of change of the speed.
So the speed can be decreasing but at an ever slower rate of decrease, Right?
 
  • #5
Right that would explain the acceleration decreasing, sorry I understood that part already, (even thought I said "and acceleration decreasing") but am having a difficult time understanding how the speed is decreasing.
 
  • #6
What force is acting on each star? Is that force directed in the same direction as their motion or not?
 
  • #7
Okay, I think I understand it now, its like if a person was on the surface of the Earth and as they got farther and farther away their speed would decrease because the force of gravity (which is the only force acting on the stars) would diminish and the person would go slower and slower as he got farther and farther away (decrease in acceleration)

Thanks! SammyS and Phinds
 
  • #8
idllotsaroms said:
Okay, I think I understand it now, its like if a person was on the surface of the Earth and as they got farther and farther away their speed would decrease because the force of gravity (which is the only force acting on the stars) would diminish and the person would go slower and slower as he got farther and farther away (decrease in acceleration)

Thanks! SammyS and Phinds

No, I don't thing you are thinking this through properly.
 

FAQ: Conceptual Question: Stars in intergalactic space with speed

What is the speed of stars in intergalactic space?

The speed of stars in intergalactic space can vary greatly, as it depends on factors such as the mass of the star, the gravitational pull of nearby objects, and any forces acting on the star. Some stars may be moving at very high speeds, while others may be relatively stationary.

How do stars in intergalactic space maintain their speed?

Stars in intergalactic space maintain their speed through inertia, which is the tendency of an object to continue moving at a constant speed in a straight line unless acted upon by an external force. In the vacuum of space, there is very little resistance to slow down the motion of stars, so they can continue moving at high speeds for a very long time.

Can stars in intergalactic space collide with each other?

Yes, stars in intergalactic space can collide with each other, although it is relatively rare. The vast distances between stars make it unlikely for them to come into contact, but in some cases, the gravitational pull of one star may cause another star to change its trajectory and potentially collide with another star or object.

How do stars in intergalactic space affect the space around them?

Stars in intergalactic space can have a significant impact on the space around them through their gravity. They can influence the movement and trajectories of nearby objects, and in some cases, they may even merge with other stars or form new systems. Additionally, stars also emit radiation and energy, which can impact the surrounding space and affect other objects.

Can stars in intergalactic space travel in a straight line forever?

In theory, stars in intergalactic space can continue moving in a straight line forever if there are no external forces acting on them. However, the presence of other objects, such as other stars or black holes, can alter their trajectory and cause them to deviate from a straight path. Additionally, the expansion of the universe may also impact the movement of stars in intergalactic space over very long periods of time.

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