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a man pushes a cylinder of mass m 1 with the help of a plank of mass m 2 as shown. There is no slipping at any contact. The horizontal component of the force applied by the man is F. find: (a) the accelerations of the plank and the centre of mass of the cylinder, and (b) magnitudes and directions of frictional forces at contact points.

a man pushes a cylinder of mass m1 with the help of a plank of mass m2 as shown. There is no slipping at any contact. The horizontal component of the force applied by the man is F. find:


(a) the accelerations of the plank and the centre of mass of the cylinder, and


(b) magnitudes and directions of frictional forces at contact points.


1615_13194_untitled.GIF

Grade:12

1 Answers

Askiitians Expert Soumyajit IIT-Kharagpur
28 Points
14 years ago

Dear Aditya Nijampurkar,

Ans:

Let us consider the following

a1=Acc of the cylinder towards right

a2=Acc of the plank towards right

β= clockwise angular Acc of the cylinder

f1= The force of friction at the point of contact of the bodies

f2=The force of friction at the bottommost surface

The eq of motions of the Plank and the cylinder are,

F - f1=m2 a2..........................(1)

(f1+f2)r=Iβ.............................(2)

f1 - f2=m1 a1.............................(3)

Now the conditions of non sleepping are

βr+a1 = a2........................(4)

βr=a2...............................(5)

Solving we get

a2=8F/(3m1+8m2)

a1=4F/(3m1+8m2)

f1=3m1 F/(3m1+8m2)

f2= - m1 F/(3m1+8m2)

The negative sign indicates that friction between the ground and the cylinder  acts in the forward direction.

 

 

 

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Regards,

Askiitians Experts
Soumyajit Das IIT Kharagpur

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