Hi,I was wondering if acceleration was a form of nonuniform speed?

[Bashyboy]

Hi,

I was wondering if acceleration was a form of nonuniform speed?

 

[sophiecentaur]

That's what it means!

 

[Bashyboy]

Well, thank you very much for answering so promptly.

 

[cjl]

Well...

Acceleration means nonuniform velocity. An object can have a uniform speed and still be accelerating (if it is following a curved path at a constant speed).

 

[sophiecentaur]

I said it the wrong way round; non-uniform speed is called / is an example of acceleration.
You are right about change of direction, of course. Mea culpa for being so sloppy.

 

[LostConjugate]

Well...

Acceleration means nonuniform velocity. An object can have a uniform speed and still be accelerating (if it is following a curved path at a constant speed).

Changing your direction is actually just a decrease in speed in one orthogonal dimension and an increase in another however, so fundamentally it is non-uniform speed.

 

[cjl]

Changing your direction is actually just a decrease in speed in one orthogonal dimension and an increase in another however, so fundamentally it is non-uniform speed.

Since speed is the magnitude of velocity, that isn't really the case.

 

[LostConjugate]

Since speed is the magnitude of velocity, that isn't really the case.

Total speed is the magnitude of velocity. Acceleration is non-uniform speed in at least 1 spatial direction.

 

[cjl]

Total speed is the magnitude of velocity. Acceleration is non-uniform speed in at least 1 spatial direction.

You're trying to invoke direction, but by definition, speed is directionally independent. If you include directional information, you're talking about velocity, not speed.

 

[LostConjugate]

You're trying to invoke direction, but by definition, speed is directionally independent. If you include directional information, you're talking about velocity, not speed.

I was commenting on your remark that acceleration means nonuniform velocity. And that you can have a uniform speed and still be accelerating. What you mean is that you can have a uniform "total" speed in all directions and still be accelerating. This makes it much more confusing than it actually is and people get confused as to why changing direction is acceleration, it makes it sound mysterious when it is not.

You can't say that your speed is uniform because you are making up for a loss in speed in one orthogonal direction by a gain in speed in another orthogonal direction. This is why they are "orthogonal".

When you go around a turn in your car you are reducing your speed in the direction you were travelling, this is why you feel the same effect as if you press on your brake.

 

[HallsofIvy]

This is a physics board and we are using the word "speed" in its technical, physics, meaning. Talking about "speed in the direction you were travelling" indicates that you are not.