The angular speed of a particle,moving in a circle of radius 20 cm ,increases from ` 2 rad //s to 40 rad//s` in 19 s the ratio of its centripetal acceleration to tangential acceleration at the end of 19 s is ,

Options

A. `400:1`
B. `1:800`
C. `1:400`
D. `800:1`

Answer

D

Explanation

`a_(T)=r alpha=0.2((omega_(2)-omega_(1)))/(t)=(0.2(40-2))/(19)=0.4`
`v_(2)=romega_(2)=0.2xx40=8`
`a_(r)=(v^(2))/(r)=(64)/(0.2)=320`
`a_(r)/(a_(T))=(320)/(0.4)=(800)/(1)``