Question

An object is moving along circumference of a circular track of radius r .what is the displacement when it covers 3/4 of the circumference

Answer 1

The $Displacement^2$= $r^2$ + $r^2$
                                                = $2(r^2)$

$Displacement= \sqrt{2r^2}$

Answer 2

displacement means the distance between the initial and final point.When the object will move to the 3/4 of the circumference the displacement will be the distance means length of hypotenuse which is made by the two radii which are perpendicular to each other.there by pythagorus rule we will get the length of hypotenuse means displacement √2r.i hope that it will help you.