1My first pink post......................
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two thin circular discs of mass 2kg and radius 10cm each are joined by a rigid massless rod of length 20cm. the axis of the rod is along the perpendicular to the plane of the disc through their centres.
this object is kept in a truck.
its friction in the floor is large enuf so that the object can roll on the truck without slipping. take x-axis as the direction of motion of the truck and z-axis as the vertically upwards direction.
if the truck has an acceleration of 9m/s^2...
calculate:
1) the force of friction on each disc..
2) the magnitude and the direction of the frictional torque acting on each disc about the cenetr of mass O of the object.
express the torque in the vector form in terms of unit vectors i,j,k...
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UP 0 DOWN 0 0 5
5 Answers
1Let f b the friction...
a the acc. of the trucktorque abt. the pt.of cnct
is Ï„=MaR
ang. acc.=α=τ/I
I =moment of inrtia abt. pt. of conct
i,e, I=1.5MR2
linear acc. is given by...=a2=αR=(2/4)α*(2/3)*9
=6 m/s2
Nw, motion of disc is
Ma-f=Ma2
(Ma is psuedo)
or f=M(a-a2)
f=2(9-6)
=6 N
am i right,....
1I=1.5MR^2
why ? [2]
am being silly i think.....
par yeh batado...........
waise ur ans are correct....i think..
1calculate moment of inertia abt the pt. of concact ....=MR2/2 +MR2
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