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A-uniform-chain-of-mass-M-and-length-L-is-hanging-from-the-table-The-chain-is-in-limiting-equilibrium-when-l-length-of-chain-over-hangs-It-is-slightly-disturbed-from-this-position-Find-the-speed-of




Question Number 23288 by Tinkutara last updated on 28/Oct/17
A uniform chain of mass M and length  L is hanging from the table. The chain  is in limiting equilibrium when l length  of chain over hangs. It is slightly  disturbed from this position. Find the  speed of the chain just after it completely  comes off the table.
AuniformchainofmassMandlengthLishangingfromthetable.Thechainisinlimitingequilibriumwhenllengthofchainoverhangs.Itisslightlydisturbedfromthisposition.Findthespeedofthechainjustafteritcompletelycomesoffthetable.
Commented by Tinkutara last updated on 28/Oct/17
Commented by Physics lover last updated on 28/Oct/17
Is it         (√(g(L−l)))  ?
Isitg(Ll)?
Commented by Physics lover last updated on 28/Oct/17
The answer given in the book is         (√((gL)/((1+μ))))  ut the answer which i got is same.     μ = (l/(L−l ))     ⇒ l = ((μL)/((1+μ)))  if  you substitute  l   in  my answer      (√(g(L−l) ))  = (√(g{L−((μL)/((1+μ)))}))  = (√(g{((L+μL−μL)/((1+μ)))}))  = (√((gL)/((1+μ))))
TheanswergiveninthebookisgL(1+μ)uttheanswerwhichigotissame.μ=lLll=μL(1+μ)ifyousubstitutelinmyanswerg(Ll)=g{LμL(1+μ)}=g{L+μLμL(1+μ)}=gL(1+μ)
Answered by Physics lover last updated on 28/Oct/17
        λ = linear mass density = ((M )/L)     ⇒ μg(L−l)λ = λgl     ⇒ μ  = ((l )/((L−l)))           let an element dx at a distance     x from edge of table.     dW_(friction )   = (−μgλdx)∙x  as friction ′s direction is opposite  to that of dist covered.   ⇒ ∫_0 ^(  W) dW =   − ∫_0 ^((L−l))  μg((M/L))x ∙dx    ⇒ W = −((Mgl(L−l))/(2L))  Using  Energy conservation  ⇒ ∣ΔK.E.∣ = ∣ΔP.E.∣ + W_(friction)   ⇒ (1/2) mv^(2 ) = ∣ g(λl)((l/2))−g(λL)((L/2))∣ − ((Mgl(L−l))/(2L))   subtitute λ = (M/L)  on solving     v = (√(g(L−l)))
λ=linearmassdensity=MLμg(Ll)λ=λglμ=l(Ll)letanelementdxatadistancexfromedgeoftable.dWfriction=(μgλdx)xasfrictionsdirectionisoppositetothatofdistcovered.0WdW=(Ll)0μg(ML)xdxW=Mgl(Ll)2LUsingEnergyconservationΔK.E.=ΔP.E.+Wfriction12mv2=g(λl)(l2)g(λL)(L2)Mgl(Ll)2Lsubtituteλ=MLonsolvingv=g(Ll)
Commented by Physics lover last updated on 28/Oct/17
Commented by Tinkutara last updated on 28/Oct/17
Thank you very much Sir!
ThankyouverymuchSir!
Commented by Physics lover last updated on 28/Oct/17
you are welcome.  BTW,did you try question no. 14   H section , laws of motion.Its  a good one too.
youarewelcome.BTW,didyoutryquestionno.14Hsection,lawsofmotion.Itsagoodonetoo.
Commented by Physics lover last updated on 28/Oct/17
hmmm.
hmmm.

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