The maximum safe speed of a vehicle on a circulartrack is `15km//h` . When the track becomes wet, the maximum safe speed is `10 km//h` .The ratio of coefficient of friction of dry track to that o0f the wet track is

Options

A. `2:3`
B. `3:2`
C. `9:4`
D. `1:1`

Answer

C

Explanation

`(v_(1))/(v_(2))=sqrt((mu_(1))/(mu_(2)))`
`(v_(1)^(2))/v_(2)^(2)=(mu_(1))/(mu_(2))`
`(15xx15)/(10xx10)=(mu_(1))/(mu_(2))`
`(9)/(4)=(mu_(1))/(mu_(2))`