A car of mass `1000kg` negotiates a banked curve of radius `90m` on a fictionless road. If the banking angle is `45^(@)` the speed of the car is:

Options

A. `20ms^(-1)`
B. `30ms^(-1)`
C. `ms^(-1)`
D. `10ms^(-1)`

Answer

b

Explanation

Here, `m = 1000kg, r = 90m, theta = 45^(@) , upsilon = ` ?
For banking, `tan theta= (upsilon^(2))/(rg)`
`upsilon^(2) = rg tan theta = 90 xx 10 tan 45^(@) = 900`
`upsilon = sqrt(900) = 30m//s` .