A block of mas m rests on a bracket of mass M. The coeff of friction b/w the block and bracket are @s and @k. The bracket rests on a frictionless surface. Show that the max force F that can be applied if the block is not to slide on the bracket is given by
[@s mg (M+m)] / (M+2m).
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3 Answers
1357
From the FBD we have
2F-f=Ma (1)
f-F=ma (2)
f=μsmg (3)
solve the above three to get answer
13572F-f=Ma (1)
f-F=ma (2)
f=μsmg (3)
dividing (1) be (2) we get
(2F-f)/(f-F)=M/m
or 2mF-mf=Mf-MF
or (2m+M)F=(m+M)f
(2m+M)F=(m+M)μsmg
or F=(m+M)μsmg(2m+M)
:)