The maximum speed with which a car driven round a curve of radius 18 m without skidding (where ,`g=10ms^(-2)` and the coefficient of friction between rubber tyres and the roadway is 0.2)is

Options

A. `36.0kmh^(-1)`
B. `18.0kmh^(-1)`
C. `21.6kmh^(-1)`
D. `14.4kmh^(-1)`

Answer

C

Explanation

Here, `V_(max)=?,r=18m,g=10ms^(-2) and mu=0.2`
`(mv_max^2)/(r)=F=muR=mumg`
`v_max=sqrt(murg)=sqrt(0.2xx18xx10)=6ms^(-1)`
`=6 xx18//5kmh^(-1)=21.6kmh^(-1)`