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A race car moves such that its position fits the relationship x = (5 m/s)t + (0.

ID: 2136996 • Letter: A

Question

A race car moves such that its position fits the relationship

x = (5 m/s)t + (0.7 m/s3)t3

where x is measured in meters and t in seconds.

(a) Plot a graph of the car's position versus time. (Do this on paper. Your instructor may ask you to turn in this work.)

(b) Determine the instantaneous velocity of the car at t = 4.8 s, by computing the average velocity using a time interval of 0.40 s (i.e, in this case, the average velocity from 4.6 s to 5 s. Repeat for time intervals of .20 s, and .10 s. In order to better see the limiting process keep exactly five significant figures in your answer).

?t = 0.40 s _______m/s

?t = 0.20 s _______ m/s

?t = 0.10 s _______m/s


(c) Compare the average velocity during the first 4.8 s with the results of (b).

The average velocity is ______m/s

Explanation / Answer

V = dx/dt = 5+0.7*3*t^2 =5+2.1*t^2