A smooth cone is rotated with an angular velocity `omega` as shown. `A` block `A` is placed at height `h` . Block has no motion relative to cone. Choose the correct options, when `omega` is increased.

Options

A. net force acting on block will increases
B. normal reaction acting on block will increase
C. `h` will increase
D. normal reaction will remain unchanged

Answer

D

Explanation

`Ncostheta=mg`
`Nsintheta=mRomega^(2)`
From Eq. `(i)` ,
`N=(mg)/(costheta)=`constant
as `theta=`constant
Net force is the resultant of `N` and `mg` and both Forces are constant.
Hence, net force is constant.

`omega=sqrt((g)/(R)tantheta)`
But `R=(h)/(tantheta)`
`:. omega=sqrt((g)/(h)tantheta)`
or `omegaprop(1)/(sqrt(h))` , `(theta="constant")`