Home
Class 12
PHYSICS
A stick o fmas density lamda=8kg//m rest...

A stick o fmas density `lamda=8kg//m` rests on a disc of radius `R=20cm` as shown in the figure. The stick makes an angle `theta=37^(@)` with the horizontal and is tangent to the disc at its upper end. Friction exists at all point of contact and assume that it is large enough to keep the system at rest. Find the friction force (in Newton) between the ground and the disc. (take `g=10m//s^(2)`)

Text Solution

Verified by Experts

The correct Answer is:
`00006.40`
`tau_(A)=0`
`N=(Mg)/2 cos theta`
For disc, `N sintheta=f+fcostheta`
`:.f=(Nsintheta)/(1+costheta)=(Mgsinthetacostheta)/(2(1+costheta)`
`M=lamdaL` and `L=r/("tan"(theta)/2)`
`f=1/2 lamda R cos theta`
`=1/2 xx8xx10xx2/10xx4/5`
`=32/5=6.40N`
Promotional Banner

Similar Questions

Explore conceptually related problems

A uniform stick of mass M is placed in a frictionless well as shown. The stick makes an angle theta with the horizontal. Then the force which the vertical wall exerts on right end of stick is :

A boy is pushing a ring of mass 2 kg and radius 0.5 m with a stick as shown in the figure. The stick applies a force of 2 N on the ring and rolls it without slipping with an acceleration of 0.3 m//s^(2) . The coeffecient of friction between the ground and the ring is large enough that rolling always occur and the coefficient of friction between the stick and the ring

Two forces of magnitude F are acting on a uniform disc kept on a horizontal rough surface as shown in the figure. Friction force by the horizontal surface on the disc is nF . Find the value of n .

A disc rotates about its aixs of symmetry in a horizontal plane at a steady rate of 3.5 revolutions per second A coin placed at a distance fo 1.25 cm form the axis of ratation remains at rest on the disc The coefficient of friction between the coin and the disc is : (g=10//s^(2))

A uniform disc of mass m and radius R is rolling up a rough inclined plane which makes an angle of 30^@ with the horizontal. If the coefficients of static and kinetic friction are each equal to mu and the only force acting are gravitational and frictional, then the magnitude of the frictional force acting on the disc is and its direction is .(write up or down) the inclined plane.

From a circular disc of radius R and mass 9M, a small disc of radius R/3 is removed as shown in figure. The moment of inertia of the remaining disc about an axis perpendicular to the plane of the disc and passing through O is

A boy is pulshing a ring of mass 3 kg and radius 0.6 m with a stick as shown in figure. The stick applies a force of 3N on the ring and rolls it without slipping with an acceleration of 0.4 m//s^(2) The coefficient of friction between the ground and the ring is large enough that rolling always occurs and the coefficeient of friction between the stick and the ring is (f)/(10) The vlaue of F is

( a ) A rigid body of radius of gyration k and radius R rolls without slipping down a plane inclined at an angle theta with the horizontal. Calculate its acceleration and the frictional force acting on it. ( b ) If the body be in the form of a disc and theta=30^(@) , what will be the acceleration and the frictional force acting on it.

A system of uniform rod of mass m and length 2R and a uniform disc of m and radius R are as shown in the figure. The moment of inertia of the system about the axis OO^' (perpendicular to plane of disc) will be

A disc has mass 9 m. A hole of radius R/3 is cut from it as shown in the figure. The moment of inertia of remaining part about an axis passing through the centre 'O' of the disc and perpendicular to the plane of the disc is :