Now take another example. A body starts from rest and reaches a velocity of 10 m/s in 4 s. The graph is as shown in the fig to the right.
Calculate the area under the graph (shaded area). It is a triangle, therefore,
Area = ½ (height × width) = ½ (10 m/s × 4 s) = ½ × 40 m = 20 m
Now imagine about the displacement traveled by the body. As the velocity increases from 0 to 10 m/s uniformly, the average velocity must be ½ (0 + 10) = 5. So the body is moving with an average velocity of 5 m/s. It goes for 4 s, therefore, its displacement is 5 × 4 = 20 m.
Again the result is the area of a velocity-time graph shows the displacement. We can prove in similar way for any type of velocity or combination of increasing, decreasing, uniform etc.
Its incomplete sir