What is the work done on a comet orbiting a star?

In summary: So while the overall work may not be zero, the work done in the direction of motion is still zero.In summary, the conversation discussed the concept of work in relation to a comet orbiting a star. It was determined that if the orbit is circular, no work is done because the force and displacement are perpendicular. However, a comet's orbit is not circular, so there will be some work done as the net force has a component in the direction of motion. The work done in the direction of motion may not be zero, but the overall work is still zero.
  • #1
ccarit3007
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If a comet is orbiting a star is there any work done? I understand that work is force * displacement, but the force must be in the direction of motion. In the case of a comet and star the star exerts a gravitational force on the comet, but this force is not in the direction of the motion of the star (as the motion is circular). Is this the correct logic? For the question in the image shown I understand that potential energy would be greatest at A and kinetic would be greatest at D, but I still am stumped on the work side of things.
 

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  • #2
You are correct that if the orbit is circular then the force and the displacement are perpendicular, so no work is done. However, a comet's orbit is not circular...
 
  • #3
phyzguy said:
You are correct that if the orbit is circular then the force and the displacement are perpendicular, so no work is done. However, a comet's orbit is not circular...
Yes, I understand that. So when you are not at point A or point D the force will not be perpendicular to the velocity (and momentum). I'm not sure exactly what this means/where I go from there? I'm guessing that means the work at A & D is 0?
 
  • #4
ccarit3007 said:
Yes, I understand that. So when you are not at point A or point D the force will not be perpendicular to the velocity (and momentum). I'm not sure exactly what this means/where I go from there? I'm guessing that means the work at A & D is 0?
Ah thinking about this again, the net force which would be directed towards the star would have a component that is in the direction of the momentum. Is this correct?
 
  • #5
ccarit3007 said:
Ah thinking about this again, the net force which would be directed towards the star would have a component that is in the direction of the momentum. Is this correct?

It would have a component of the force directed in the direction of motion, yes.
 

What is the work done on a comet orbiting a star?

The work done on a comet orbiting a star refers to the amount of energy required to change the comet's velocity or position in its orbit around the star. This work is typically done by the gravitational force of the star, which pulls the comet towards it and causes it to follow a curved path.

How is the work calculated for a comet orbiting a star?

The work done on a comet orbiting a star can be calculated using the formula W = Fd, where W is the work, F is the force exerted by the star on the comet, and d is the distance over which the force acts. In this case, the force is the gravitational force and the distance is the circumference of the comet's orbit.

What factors affect the amount of work done on a comet orbiting a star?

The amount of work done on a comet orbiting a star depends on several factors, including the mass of the star, the mass and speed of the comet, and the distance between the star and the comet. The closer the comet is to the star and the faster it is moving, the more work will be done on it by the star's gravitational force.

Why is the work done on a comet orbiting a star important?

The work done on a comet orbiting a star is important because it determines the comet's trajectory and overall behavior in its orbit. The amount of work done on the comet can also affect its composition and physical characteristics over time as it interacts with the star's gravity.

Can the work done on a comet orbiting a star change over time?

Yes, the work done on a comet orbiting a star can change over time. This is because the comet's velocity and position in its orbit can change due to external factors such as interactions with other objects in the solar system. These changes can alter the amount of work being done on the comet by the star's gravitational force.

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