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

• Bashyboy
In summary, acceleration is a form of nonuniform speed, which means that an object can have a uniform speed and still be accelerating if it is following a curved path at a constant speed. Changing direction is an example of acceleration because it involves a decrease in speed in one direction and an increase in another. However, speed is directionally independent, and including directional information makes it velocity instead of speed. When going around a turn, the decrease in speed in one direction is made up for by an increase in speed in another direction, making it non-uniform speed.
Bashyboy
Hi,

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

That's what it means!

Well, thank you very much for answering so promptly.

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).

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.

cjl said:
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.

LostConjugate said:
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.

cjl said:
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.

LostConjugate said:
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.

cjl said:
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.

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.

## What is acceleration?

Acceleration is the rate of change of an object's velocity over time. It is a vector quantity, meaning it has both magnitude and direction.

## How is acceleration different from speed?

Speed refers to the rate at which an object is moving, while acceleration refers to the rate at which an object's speed is changing. In other words, acceleration measures the change in speed over time.

## What is nonuniform speed?

Nonuniform speed is when an object's speed changes at a non-constant rate. This means that the object is accelerating or decelerating, rather than moving at a constant speed.

## Is acceleration always caused by a change in speed?

No, acceleration can also occur when there is a change in direction, even if the speed remains constant. This is known as centripetal acceleration.

## How is acceleration measured?

Acceleration is typically measured in meters per second squared (m/s²) or feet per second squared (ft/s²). It can be calculated by dividing the change in an object's velocity by the time it takes for that change to occur.

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