Clarification between average velocity and average speed

In summary, average velocity is calculated by dividing total displacement by total time. Average speed is calculated by dividing total distance by total time. For constant acceleration in a straight line, the average speed and velocity can also be calculated using the formula (v1+v2)/2.
  • #1
cmkc109
103
0
To find average velocity, you do total displacement over total time
To find average speed, you add up the speeds / total speeds there are? (Eg. (10+20)/2)

Am I correct?
 
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  • #2
cmkc109 said:
To find average velocity, you do total displacement over total time

Correct.

To find average speed, you add up the speeds / total speeds there are? (Eg. (10+20)/2)

No, you take the total distance along the path traveled, over the total time. For "total distance", imagine tracing out the path with a string, then straightening the string and measuring its length with a ruler.
 
  • #3
thanks for your reply! but when do you use v1 + v2 /2 ? or did i remember this wrong?
 
  • #4
cmkc109 said:
thanks for your reply! but when do you use v1 + v2 /2 ? or did i remember this wrong?

You can use (v1+v2)/2 for the average speed if you first moved with speed v1 and then with speed v2 for the same amount of time. (not for the same amount of distance).

For constant acceleration in a straight line, the average speed (and velocity as well) is [itex] \frac {v_i + v_f}{2} [/itex]. the average of initial and final speed.
 
  • #5
cmkc109 said:
thanks for your reply! but when do you use v1 + v2 /2 ? or did i remember this wrong?
Hi. I think you forgot some parentheses.

You use that formula when acceleration is constant and you need to find the velocity at a time midway between the time that you measure velocity as v1 and the time you measure velocity as v2.
 

FAQ: Clarification between average velocity and average speed

What is the difference between average velocity and average speed?

The main difference between average velocity and average speed is that velocity is a vector quantity while speed is a scalar quantity. This means that velocity has both magnitude and direction, while speed only has magnitude.

How are average velocity and average speed calculated?

Average velocity is calculated by dividing the total displacement by the total time, while average speed is calculated by dividing the total distance traveled by the total time. In other words, average velocity takes into account the direction of motion while average speed does not.

When is it more appropriate to use average velocity over average speed?

Average velocity is more appropriate to use when the motion is not in a straight line and changes direction, as it takes into account the changes in direction. For example, when calculating the average velocity of a car driving on a curved road, while average speed would be more appropriate for a car driving on a straight road.

Can average velocity and average speed have the same value?

Yes, it is possible for average velocity and average speed to have the same value. This occurs when the motion is in a straight line and there is no change in direction. In this case, the magnitude of the velocity and speed are the same.

How are average velocity and average speed related?

Average velocity and average speed are related in that they both measure the rate of motion. However, they differ in that average velocity takes into account the direction of motion while average speed does not. Additionally, average velocity can be calculated using average speed, but the reverse is not true.

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