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A-hemispherical-bowl-of-radius-R-0-1-m-is-rotating-about-its-own-axis-which-is-vertical-with-an-angular-velocity-A-particle-of-mass-10-2-kg-on-the-frictionless-inner-surface-of-the-bowl-is-




Question Number 24032 by Tinkutara last updated on 11/Nov/17
A hemispherical bowl of radius R = 0.1  m is rotating about its own axis (which  is vertical) with an angular velocity ω.  A particle of mass 10^(−2)  kg on the  frictionless inner surface of the bowl is  also rotating with the same ω. The  particle is at a height h from the bottom  of the bowl.  It is desired to measure g (acceleration  due to gravity) using the set up by  measuring h accurately. Assuming  that R and ω are known precisely and  that the least count in the measurement  of h is 10^(−4)  m, what is the minimum  possible error Δg in the measured value  of g?
AhemisphericalbowlofradiusR=0.1misrotatingaboutitsownaxis(whichisvertical)withanangularvelocityω.Aparticleofmass102kgonthefrictionlessinnersurfaceofthebowlisalsorotatingwiththesameω.Theparticleisataheighthfromthebottomofthebowl.Itisdesiredtomeasureg(accelerationduetogravity)usingthesetupbymeasuringhaccurately.AssumingthatRandωareknownpreciselyandthattheleastcountinthemeasurementofhis104m,whatistheminimumpossibleerrorΔginthemeasuredvalueofg?
Commented by ajfour last updated on 11/Nov/17
Commented by Tinkutara last updated on 12/Nov/17
Thank you very much Sir!  But why − in ω^2 Δh? Errors are always  + and added.
ThankyouverymuchSir!Butwhyinω2Δh?Errorsarealways+andadded.
Commented by ajfour last updated on 11/Nov/17
Ncos θ=mg  Nsin θ =mω^2 Rsin θ  ⇒ ω^2 Rcos θ = g     ....(i)  and    h=R(1−cos θ)  ⇒    g=ω^2 (R−h)          △g =−ω^2 △h  ⇒  △g = −((g/(Rcos θ)))△h   ∣(△g)_(min) ∣ = (((9.8)/(0.1)))×10^(−4)  m/s^2                       =9.8×10^(−3)  m/s^2  .
Ncosθ=mgNsinθ=mω2Rsinθω2Rcosθ=g.(i)andh=R(1cosθ)g=ω2(Rh)g=ω2hg=(gRcosθ)h(g)min=(9.80.1)×104m/s2=9.8×103m/s2.
Commented by NECx last updated on 12/Nov/17
when you draw with this app do you  use your hand or a stylus pen?    i′m asking because i try to use it  with my hands but my drawings are  not as nice as the ones i see you  post here.
whenyoudrawwiththisappdoyouuseyourhandorastyluspen?imaskingbecauseitrytouseitwithmyhandsbutmydrawingsarenotasniceastheonesiseeyouposthere.
Commented by ajfour last updated on 12/Nov/17
dont have stylus , i draw with  finger after necessary zoom  using Handraw.
donthavestylus,idrawwithfingerafternecessaryzoomusingHandraw.
Commented by ajfour last updated on 12/Nov/17
this implies that if measured  h is little greater than true  value, then calculated g will be  less than the true value..
thisimpliesthatifmeasuredhislittlegreaterthantruevalue,thencalculatedgwillbelessthanthetruevalue..
Commented by NECx last updated on 12/Nov/17
ok boss
okboss

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