# Physics: 1d Motion-Instantaneous Velocity vs Average.

## Main Question or Discussion Point

Trying to create a table with time and instantaneous velocity. (the tables- http://i.imgur.com/8DZsu.png ) How do I go from using the Average Velocity to the Instantaneous Velocity?

Instantaneous Velocity is the V_avg at t_1 + (delta-t)/2 how do I use this with my data.

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## Answers and Replies

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Khashishi
You have to make some assumptions about the smoothness of the data, because you lose some information from only having sampled data. See if you can fit the data to a particular model function. If you can't, then you can just estimate the instantaneous velocity = the average velocity at the center of each averaging period. The centers of your averaging periods are between each sample point. If you want the instantaneous velocity at your sample points, then you can take the midpoint between each pair of average velocities. Of course, it's all very approximate.

So between t1=.05 and t2=.10 you take the mid point of the average velocities which is 30 + 35 = 65/2 = 32.5cm/s? Thus at t2 instantaneous velocity = 32.5cm/s?