B How Do You Calculate the Final Vector of a Rock Ejected from a Spaceship?

[DeckSmeck]

I fly in a spaceship on a 2d plane (for simplicity sake) in zero G. I eject a rock 90 degrees right to my forward vector. What does the equation look like if I want the final vector of the rock?

I know the final speed of the rock is 100.

What variables need to be known about the ship and rock?

 

[phinds]

I fly in a spaceship on a 2d plane (for simplicity sake) in zero G. I eject a rock 90 degrees right to my forward vector. What does the equation look like if I want the final vector of the rock?

It will be the equation for a straight line

What variables need to be known about the ship and rock?

To get the exact equation, you'll need the speed of your ship and the speed with which you eject the rock (and to be fully accurate, the place on the graph where the rock gets ejected, but for simplicity you could just take that as being the origin.

If, on the other hand, you were "ejecting a photon", you would get a completely different result. It would still be a straight line, but it would be just a horizontal line* since the motion of your ship would have no effect on the photon.

* I'm assuming your ship is traveling in the postie Y direction.

 

[DeckSmeck]

It will be the equation for a straight line

To get the exact equation, you'll need the speed of your ship and the speed with which you eject the rock (and to be fully accurate, the place on the graph where the rock gets ejected, but for simplicity you could just take that as being the origin.

If, on the other hand, you were "ejecting a photon", you would get a completely different result. It would still be a straight line, but it would be just a horizontal line since the motion of your ship would have no effect on the photon.

Speed or velocity?

 

[phinds]

Speed or velocity?

speed or velocity WHAT ?

 

[DeckSmeck]

If, on the other hand, you were "ejecting a photon", you would get a completely different result. It would still be a straight line, but it would be just a horizontal line* since the motion of your ship would have no effect on the photon.

* I'm assuming your ship is traveling in the postie Y direction.

Not talking about photons. Just a rock. Talking about photons in a different thread. If you want to talk about photons we can talk there.

 

[DeckSmeck]

speed or velocity WHAT ?

I understand these terms describe different things.

 

[phinds]

I understand these terms describe different things.

And what is it that you want to know about as regards this thread. Your post

Speed or velocity?

was meaningless to me.

 

[DeckSmeck]

And what is it that you want to know about as regards this thread. Your post

was meaningless to me.

Ok. Maybe someone else can come up with an equation. I will check tommorrow.

 

[phinds]

Ok. Maybe someone else can come up with an equation. I will check tommorrow.

The equation is utterly trivial. If the plane is flying in the postive Y direction with velocity v1 and the rock is ejected to the right with velocity v2 as the plane passes the origin, then the equation is y=(v1/v2)x

 

[russ_watters]

I fly in a spaceship on a 2d plane (for simplicity sake) in zero G. I eject a rock 90 degrees right to my forward vector. What does the equation look like if I want the final vector of the rock?

I know the final speed of the rock is 100.

What variables need to be known about the ship and rock?

I recommend reading this link on vector addition:
https://www.physicsclassroom.com/class/vectors/Lesson-1/Vector-Addition

It looks to me like you also need either the speed of the spaceship or the ejection speed of the rock, since you have specified the final speed of the rock (which seems odd...).

Also:

Speed or velocity?

You will get better responses if you write your questions in complete sentences, containing complete thoughts. I believe I know what this question was referring to, but you should have written it out fully.