Question

A body completes one round of a circle of radius 'R' in 20 second. The displacement of the body after 45 second is ?

Answer 1

it is √2 r by solving

Answer 2

Answer:

The displacement of the body after 45 second is $R\sqrt{2}$.

Explanation:

Given that,

Radius = R

A body completes one round of a circle of radius 'R' in 20 second.

Let A is the point where the body started its motion. After 20 sec the body returns at point A and again after 40 sec the body returns at point A.

In 5 sec, the body completes quarter of circle.

Therefore, The body will be at B after 45 sec.

The displacement AB will be

Using Pythagoras theorem

$AB= \sqrt{r^2+r^2}$

$AB= \sqrt{R^2+R^2}$

$AB= R\sqrt{2}$

Hence, The displacement of the body after 45 second is $R\sqrt{2}$.