Given mA=30 kg ,mB=10 kg,mC=20 kg Between A and B friction coefficient Nu1=0 3,between B and C friction coefficient Nu2=0 - Physics - Laws Of Motion

Question

Given mA=30 kg ,mB=10 kg,mC=20 kg Between A and B friction
coefficient Nu1=0 3,between B and C friction coefficient Nu2=0 2
and between C and ground Nu3=0 1 The least horizontal force F to
start the motion of any part of the system of three blocks resting
upon one another as shown

(a) 60 N (b) 90 N (c) 80 N (d) 150 N

Apurba Paul · Accepted Answer

Dear Student,

Please find below the solution to the asked query:

Frictional force between A and B is F1=μ1m1g=0
3×30×10=90Frictional froce between B and C is  F2=μ2m1+m2g=0
2×40×10=80And Frictional force between ground is F3=μ3m1+m2+m3g=0
1×60×10=60So if you apply 60 N force then whole block will starts moving with respectto ground
 Hence correct answer is (a) 60 N

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