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Question-82726




Question Number 82726 by mr W last updated on 23/Feb/20
Commented by mr W last updated on 23/Feb/20
mass m_1  and m_2  are released from the  top of a wedge simutaneously. assume  that mass m_1  reaches the bottum of  the wedge firstly. find the velocity of  the wedge at this moment.  all surfaces are frictionless.
massm1andm2arereleasedfromthetopofawedgesimutaneously.assumethatmassm1reachesthebottumofthewedgefirstly.findthevelocityofthewedgeatthismoment.allsurfacesarefrictionless.
Commented by TawaTawa last updated on 23/Feb/20
Sir please i need help, i have post the question several time.  i repost now  Q82729.  Or the question is not correct so that i can stop  posting it. Please help. Thanks sir.
Sirpleaseineedhelp,ihavepostthequestionseveraltime.irepostnowQ82729.Orthequestionisnotcorrectsothaticanstoppostingit.Pleasehelp.Thankssir.
Commented by ajfour last updated on 23/Feb/20
Commented by TawaTawa last updated on 23/Feb/20
Sir, i have typed the question. please check. God bless you sir.  Q82729.
Sir,ihavetypedthequestion.pleasecheck.Godblessyousir.Q82729.
Commented by ajfour last updated on 23/Feb/20
Commented by ajfour last updated on 23/Feb/20
a_1 =gsin θ_1 −Acos θ_1   a_2 =gsin θ_2 +Acos θ_2   (h/(sin θ_1 ))=(1/2)(gsin θ_1 −Acos θ_1 )t^2   ⇒ ((2h)/(sin θ_1 ))=gt^2 sin θ_1 −Vtcos θ_1   ..(i)  [ from above eq. we get t(V)]  u=(gsin θ_1 −Acos θ_1 )t      = gtsin θ_1 −Vcos θ_2     .....(ii)  v=gtsin θ_2 +Vcos θ_2       .....(iii)  m_1 ucos θ_1 +(M+m_1 +m_2 )V           = m_2 vcos θ_2               .....(iv)  using (i), (ii), (iii), (iv)  V is obtained...
a1=gsinθ1Acosθ1a2=gsinθ2+Acosθ2hsinθ1=12(gsinθ1Acosθ1)t22hsinθ1=gt2sinθ1Vtcosθ1..(i)[fromaboveeq.wegett(V)]u=(gsinθ1Acosθ1)t=gtsinθ1Vcosθ2..(ii)v=gtsinθ2+Vcosθ2..(iii)m1ucosθ1+(M+m1+m2)V=m2vcosθ2..(iv)using(i),(ii),(iii),(iv)Visobtained
Commented by mr W last updated on 23/Feb/20
wonderful solution sir!  we can get  V=((8gh)/(cos θ_1 {((4 tan θ_1 (M+m_1 sin^2  θ_1 +m_2 sin^2  θ_2 ))/(m_2 sin 2θ_2 −m_1 sin 2θ_1 ))−1}^2 −1))
wonderfulsolutionsir!wecangetV=8ghcosθ1{4tanθ1(M+m1sin2θ1+m2sin2θ2)m2sin2θ2m1sin2θ11}21
Commented by mr W last updated on 24/Feb/20
what′s the condition that m_1  reaches  the bottom firstly?
whatstheconditionthatm1reachesthebottomfirstly?
Commented by ajfour last updated on 24/Feb/20
If   t_1 < t_2  ,   m_1  reaches first.  a_1 =gsin θ_1 −Acos θ_1   a_2 =gsin θ_2 +Acos θ_2   (1/2)a_1 t_1 ^2 =(h/(sin θ_1 ))   ,   (1/2)a_2 t_2 ^2 =(h/(sin θ_2 ))    t_1 =(√((2h)/(a_1 sin θ_1 ))) ,  t_2 =(√((2h)/(a_2 sin θ_2 )))  N_1 =m_1 gcos θ_1 +m_1 Asin θ_1   N_2 =m_2 gcos θ_2 −m_2 Asin θ_2   N_2 sin θ_2 −N_1 sin θ_1 =MA  A is determined from above 3 eqs.  hence we have a_1  , a_2 .  Then the condition can be  expressed..
Ift1<t2,m1reachesfirst.a1=gsinθ1Acosθ1a2=gsinθ2+Acosθ212a1t12=hsinθ1,12a2t22=hsinθ2t1=2ha1sinθ1,t2=2ha2sinθ2N1=m1gcosθ1+m1Asinθ1N2=m2gcosθ2m2Asinθ2N2sinθ2N1sinθ1=MAAisdeterminedfromabove3eqs.hencewehavea1,a2.Thentheconditioncanbeexpressed..
Commented by mr W last updated on 24/Feb/20
clear! thanks!
clear!thanks!

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