In the motorcycle stunt called " the well of death" the track is vertical cylindrical surface of 18 m radius.take the motorcyle to be a point mass and `mu=0.8`. The minimum angular speed of the motorcycle to prevent him from sliding down should be

Options

A. 6/5 rad/s
B. 5/8 rad/s
C. 25/3 rad/s
D. none of these

Answer

B

Explanation

`N=mromega^(2).....(i)`
`mu N=mg....(ii)`
From (i) and (ii)
`mu(mr omega^(2))=mg`
`omega^(2)=g/(mur)=10/(0.8xx18)`
`omega=5/8 rad//s`