Question

Calculate the velocity of segment D: My answer is 1.5 m/s. Is it correct and why?

Answer 1

The given figure is a position time graph. And the slope of position time graph gives the velocity of the object.

As we know two points on the line segment D, we can calculate the slope of the line.

In the given figure,the points (3 , 3) and (5 ,0) lies on the line segment D.

So, the slope of the line segment D is

  

Hence, the velocity of the segment D is -1.5 m/s (the negative sign is indicating the backward motion of the object).

Method 2 :

From the graph , we can see that in the segment D, the initial position of the object was at x = 3 m and the final position was at x = 0 m. And the total time taken by object in moving from x =3 m to x = 0 m is (5 - 3 =) 2 seconds.

So, total displacement = -3 m and

time taken = 2 s

So,   

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