Q.

A large drum having radius R is spinning around its axis with angular velocity ω, as shown in figure. The minimum value of ω so that a body of mass M remains stuck to the inner wall of the drum, taking the coefficient of friction between the drum surface and mass M as μ, is:   [2026]

1 μgR  
2 g2μR  
3 gμR  
4 2gμR  

Ans.

(3)

N=mω2r,    mg=μN

μ×mω2r=mg

ω=gμr