A particle goes round a circular path with uniform velocity v. After describing half the circle, the average acceleration of the particle (if its radius is r) is:

Options

A. `(v^(2))/(r )`
B. `(v^(2))/(pir)`
C. `(2v^(2))/(r )`
D. `(2v^(2))/(piv)`

Answer

D

Explanation

Here change in velocity after completing half revolution is = V-(-u) = 2v
`therefore`   .Time taken in describing half of rotation=`(pir)/(v)=t(say)`
  average acceleration = `("Velocity change")/("Time")`
`(2v)/(t)=(2v)/(pir).v(2v^(2))/(pir)`
=`(2v^(2))/(pir)`