A particle is moving in a circle of radius `r` centred at `O` with constant speed `u`. What is the change in velocity in moving from `A "to" B (/_ AOB = 40^@)` ?

Options

A. ` 2u sin 20^@`
B. `4u sin 40^@`
C. `2u sin 40^@`
D. `u sin 40^@`

Answer

A

Explanation

Change in velocity `=overset(-)(V)f-overset(-)V_(i)`
Its magnitude `|triangle overset(-)V|=sqrt(u^(2)+u^(2)-2u.u cos 40^(@)) |triangle overset(-)v|=2u sin 20^(@)`