Centripetal acceleration

[inaccensa]

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A satellite has acceleration since the vetoer velocity is changing direction. Isn't the velocity of this satellite 0units? Velocity is change in displacement and when it is moving in a circle, the displacement is zero,so velocity must be zero. wouldn't acceleration also be zero units? I'm confused😕

 

[ilovemcat]

A satellite has acceleration since the vetoer velocity is changing direction. Isn't the velocity of this satellite 0units? Velocity is change in displacement and when it is moving in a circle, the displacement is zero,so velocity must be zero. wouldn't acceleration also be zero units? I'm confused😕

Velocity isn't just magnitude, it's direction too.

 

[bbottle]

I want to point out two things.

First, The instantaneous velocity of the satellite is not 0. The average velocity, is 0 (net displacement/time). This is because every instantaneous velocity vector is canceled out by a vector pointing in a different direction over the course of one orbit.

Second, acceleration can do two things. It can either change the velocity's magnitude or change the direction of an object. In this case, the acceleration is changing the direction of the satellite. So, even though the velocity's magnitude does not increase, an acceleration is required to keep the direction of the velocity changing. If there was no acceleration, the satellite would go off in a straight line.

 

[inaccensa]

yes indeed,but what about the magnitude? The instantaneous velocity shouldn't be zero, but how about the average velocity or velocity once around the circle?😱

 

[inaccensa]

I want to point out two things.

First, The instantaneous velocity of the satellite is not 0. The average velocity, is 0 (net displacement/time). This is because every instantaneous velocity vector is canceled out by a vector pointing in a different direction over the course of one orbit.

Second, acceleration can do two things. It can either change the velocity's magnitude or change the direction of an object. In this case, the acceleration is changing the direction of the satellite. So, even though the velocity's magnitude does not increase, an acceleration is required to keep the direction of the velocity changing. If there was no acceleration, the satellite would go off in a straight line.

you answered my question while I was typing it up Thanks
So it is safe to assume that the magnitude is zero.

 

[bbottle]

What magnitude are you talking about?

The magnitude of average velocity is 0.
The magnitude of instantaneous velocity at any given point is NOT 0.

The CHANGE in the velocity's magnitude can be 0 even if there's an acceleration (if the acceleration is only changing the object's direction).

 

[inaccensa]

What magnitude are you talking about?

The magnitude of average velocity is 0.
The magnitude of instantaneous velocity at any given point is NOT 0.

The CHANGE in the velocity's magnitude can be 0 even if there's an acceleration (if the acceleration is only changing the object's direction).

Precisely what you said. I think I have my answer. Thanks

 

[VicodinMan]

What magnitude are you talking about?

The magnitude of average velocity is 0.

Average velocity = 0 only when the satellite does 1 complete rotation since the vectors for its speed cancel out.

If you're looking at less than 1 rotation, then you'll have to sum up the vectors and see what cancels out to figure out its average speed.

 

[bbottle]

Average velocity = 0 only when the satellite does 1 complete rotation since the vectors for its speed cancel out.

If you're looking at less than 1 rotation, then you'll have to sum up the vectors and see what cancels out to figure out its average speed.

Agreed that average velocity is 0 only when 1, 2, 3, etc. full revolutions are complete. But couldn't we also say average velocity is 0 in general for the motion of the satellite? In other words, when time = infinity, the average velocity is 0.