Q.

A particle is moving with constant speed in a circular path. When the particle turns by an angle 90°, the ratio of instantaneous velocity to its average velocity is π:x2. The value of x will be                  [2023]

1 1  
2 2  
3 7  
4 5  

Ans.

(2)

AB=R2

Let instantaneous velocity be v, time,

t=Arc lengthv=2πR4v=πR2v

Average velocity, <v>=ABt=R2(2v)πR=22vπ

  vv=π22