Question

Q A PARTICLE START MOVING FROM REST STATEVALONG A STRAIGHT LINE UNDER ACTION OF A CONST. F & TRAVEL DIST. X IN FIRST 5 sec THE DIST. TRAVELLED IN NEXT 5 sec WILL BE=?

QA CUBE OF A SIDE a IS HEATED TO RAISE ITS TEMP. BY 3*C IF Y IS COEFF. OF VOL. EXPANSION THEN TOTAL INCREASE IN AREA=? (ANS 12Yasqure. )

 WAVES & OCILL.                 Q OBSV. IS MOVING TOWARDS A SOURCE AT REST WITH 30m/s if sound is sounding a sound of freq 500Hz & speed of sound is 300m/s then wavelenth by obsv. =?

Q TEMP. OF GAS INCREASED BY 2K KEEPING PRESS. CONST. SPEED OF SOUND IN GAS=?    ans=1.22m/s

Q THE MASS OF ELEVATOR = 4000kg .STARTING FROM REST HOW MUCH DIST. WILL IT RISE IN 2s IF TENSION =56 kN .  I want to know why we use ,' a ' for cal. dist. why 'a+g' is NOT use.

Joshi sir comment

 

by formula s = ut + 1/2 a t2

u = 0 [given]

so       s = 1/2 a (5)2= 25a/2       for first 5 sec.

and    s = 1/2 a (10)2 = 50a        for total 10 sec. from start

so for next 5 sec. distance = 50a - 25a/2 = 75a/2

 

answer :  a'3 = a3 (1+ γ3)     here a' is the side of the cube after heating it

so a' = a (1+3γ)1/3

so area increment = 6a'2 -  6a2 = 6a2 [(1+3γ)2/3 - 1] = 6a2 [ 2γ] = 12γa2

Please submit all the questions seperately. 

 

λ = v/n = 300/500 

 

i think you are asking about increment in speed

so according to formula v'/v  = [(T+2)/T]1/2 

or v'/v = 1 + (1/T)

so v' - v = v(1/T) = 332*1/273 =  1.22       here 332 is the speed of sound at 273K

 

 

when a machine works , you should not count gravity, for example if we raise our hand upword with uniform velocity then gravity makes no problem in it because our hand is working by our internal capabilitites

 

 

 

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