Speed at 5 Seconds on Linear Plot with Slope 5.0 m/s2

[fatmike6305]

A linear plot of speed versus elapsed time has a slope of 5.0 m/s2 and a vertical intercept of 5.0 m/s.
(a) What is the change in speed in the time interval between 4.0 seconds and 6.0 seconds?
The answer is 10, which completely makes sense to me.
But...

(b) What is the speed when the elapsed time is equal to 5.0 seconds?
5.0 m/s2 after 5 seconds, i thought the speed would be 25 (speed starts at 0)? I'm not sure where the vertical intercept comes in.

 

[mukundpa]

What is speed at t = 0 ?

 

[thomate1]

I would like to clarify that the speed at 5 seconds would actually be 30 m/s, not 25 m/s. This is because the vertical intercept of 5.0 m/s is added to the slope of 5.0 m/s2 multiplied by the elapsed time of 5 seconds. The vertical intercept represents the initial speed at time zero, which in this case is 5.0 m/s. Therefore, the final speed at 5 seconds would be 5.0 m/s + (5.0 m/s2 * 5 seconds) = 30 m/s.

Additionally, the change in speed in the time interval between 4.0 seconds and 6.0 seconds would be 10 m/s. This is calculated by finding the difference in speed at these two times, which would be 35 m/s at 6.0 seconds and 25 m/s at 4.0 seconds. Therefore, the change in speed would be 35 m/s - 25 m/s = 10 m/s.

In summary, the vertical intercept on a linear plot of speed versus elapsed time represents the initial speed at time zero, and should be taken into consideration when finding the speed at a specific time. The slope of the plot represents the rate of change of speed over time, and can be used to calculate the change in speed over a given time interval.