Question

how to find out velocity by the graph in angle displacement and time

Answer 1

I would explain this from the very basics of kinematics.

For a line, slope= (change in y coordinates)/(change in x coordinates)

In displacement time graph, displacement is on Y axis and time on X axis.

Velocity = displacement / time

From both the equation, it can be inferred that in a displacement time graph, slope of the line represents velocity.

Since, slope = tan theta;

Thus V1 / V2 = tan 30 / tan 60 = 1 / √3.

Since the order of ratio is not defined, hence the answer can be either √3 or 1 / √3.