# Instantaneous velocity

## Homework Statement

Is it possible for the instantaneous velocity of an object at some time, t1, to not be parallel to the average velocity over a short time interval, Δt=t2-t1? If it is not possible, explain why not. If it is possible, explain what this situation implies about the motion of the object.

## The Attempt at a Solution

i would say it's possible when acceleration is zero but I'm not sure

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## Homework Statement

Is it possible for the instantaneous velocity of an object at some time, t1, to not be parallel to the average velocity over a short time interval, Δt=t2-t1? If it is not possible, explain why not. If it is possible, explain what this situation implies about the motion of the object.

## The Attempt at a Solution

i would say it's possible when acceleration is zero but I'm not sure

Are you saying that it is possible for the instantaneous velocity to not be parallel to the average velocity when the acceleration is zero?

Are you saying that it is possible for the instantaneous velocity to not be parallel to the average velocity when the acceleration is zero?
yes but I'm not sure

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yes but I'm not sure
1. What do you need to do to find the average velocity, i.e. what is an expression that will allow you to calculate it?
2. If an object has initial velocity v1 to the right at time t1 and its acceleration is zero, how will its velocity change at some later time t2?
3. Given (1) and (2) above, what is the average velocity of this object from time t1 to time t2?

1. What do you need to do to find the average velocity, i.e. what is an expression that will allow you to calculate it?
2. If an object has initial velocity v1 to the right at time t1 and its acceleration is zero, how will its velocity change at some later time t2?
3. Given (1) and (2) above, what is the average velocity of this object from time t1 to time t2?
1) Δf/Δt
2)The velocity won't change because the acceleration which is the change in velocity is zero
3)i don't know how i can get this without the velocity and time

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Two points for your answer in 1. (a) Velocity is a vector and so is average velocity. You don't show a vector equation; (b) What is the meaning of f in Δf/Δt?
For 3 think again. If the velocity is v1 to the right at t1 and it doesn't change, what could it be at time t2?

Two points for your answer in 1. (a) Velocity is a vector and so is average velocity. You don't show a vector equation; (b) What is the meaning of f in Δf/Δt?
For 3 think again. If the velocity is v1 to the right at t1 and it doesn't change, what could it be at time t2?
velocity at t2 would still be the same if it does not change

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velocity at t2 would still be the same if it does not change
Good. Now how do you think the instantaneous velocity compares with the average velocity when the acceleration is zero? If the two are the same, why are they? If they are different, in what way?

It's going to be the same because there is no change in acceleration

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It's going to be the same because there is no change in acceleration
That's not the reason. When the acceleration is zero, the average velocity is the same as the instantaneous velocity because something other than the acceleration is not changing. What is that?