Question

an insect of a mass m= 3 kg is inside a vertical drum of radius 2 m that is rotation with an angular velocity of 5 rad s-1 . the insect doesent fall . then the minimum coefficient of friction required is ?​

Answer 1

$\huge{\underline{\tt{\red{Answer-}}}}$

Forces action {refer the attachment}

• centrifugal force = mω2r
• Reaction force R
• friction force μR
• weight of insect mg

where m is mass of insect, r is radius of drum and μ is friction coefficient.

Reaction force is same as centrifugal force. hence friction coefficient is obtained from,

$\mu R = \mu m\omega^2r = mg \ or \ \mu = \dfrac{g}{(\omega^2r)} = \dfrac{9.8}{(5\times5\times2)} = 0.2$