Question

a body covered a distance of 5m along a semicircular path.the ratio of distance to displacement is?

(a)11:7 (b)12:5 (c)7:5 (d)8:3

Answer 1

The distance is 5 m which is equal to the half of the circumference of the circular path.
Hence,
$$\begin{gathered} \frac{circumferenceofcircle}{2}=5 \\ \Rightarrow \frac{2\pi r}{2}=5 \\ \Rightarrow r=\frac{5}{\pi } \end{gathered}$$
The displacement is the shortest distance between two points. For the semicircular path, the diameter of the circle is the displacement.
Therefore, displacement = 2r = 10/π
therefore, the ratio of distance to displacement,
5 : 10/π =π :2 = 11 : 7