Doppler Effect with acceleration

just take the velocity of the source at the instant it leaves the signal and the velocity of the detector when it receives it in the frequency equation.

after t=4 seconds, source gives the signal, at that time velocity of source and observer both is 40m/s
Substituting these values in the equation I don't get the correct answer :(
answer is 2340.8 Hz

its not a straight forward sum ,

btw frm where did u get this sum swordfish ? ekdam khatarnak sum hai

suppose source emits a wave at time t₁ wich is going to be received by observer at time t = 4

now for the wave emitted by the source

λ_t = λ_o - [(v_{source at t} ) T_o + 12aT_o² ]
= λ_o - (at T_o + 12aT_o² ) ...(1)

now for finding t

1000 - 12 ( 10 ) (4²) - 12(10)t² = v(4-t)

i.e distance that the wave emitted by source at time t needs to travel to reach observer at t=4 will be covered by the wave with vel v in time (4-t)

find t from here

now , this wave and observer meet at t=4 ,
now let T = time period of the wave as detected by observer

so at time 4-T , observer and this wave are at a distance λ_t wich is the wavelength of the wave .

and at time 4 sec , observer detects this wave .

so vT + v(_{observer at time 4-T}) T + 1/2 aT² = λ_t

so frm 1

vT + v(_{observer at time 4-T}) T + 1/2 aT² = λ_o - (at T_o + 12aT_o² )

frm this eqn find T , and the freq received by observer at t=4 will be 1/T

here T_o = 1/f_o = 1/2000 , λ_o = v_wave/f_o

u will get t = 0.94832 sec

and freq received by observer = 2340.777 Hz

THanks...How did yo solve it? asked anyone or self?

solved it myself ,whom will i ask ????? but it took me half an hour just to frame the eqns !! btw i completed waves just a day ago, hence was able to solve :P, btw if u remember HCV me bhi ek accn ka sum hai on doppler , that sum helps a bit here

I thought you might have asked your teachers.....
Yeah HCV last sum...I solved it....it helps very little...
How manny days did you take to complete theory + problems in waves?

solved HCV both chapters(very very easy sums ) in 1 day
solved sir's asg( easy sums ) in 1 day

By this do you mean that sums in HCV/asg. are easy for you or you solved only easy sums from them? [3]

@Qwerty, Hope u clear IIT this year.

After that, I may take all of your assignment papers. You won't mind me giving me na? :) :) It might help me.

are HCV sums are easy .. and si's asg on waves was relatively easy ( wich hapens only rarely )

thats bcz waves is such a chapter that u cant ask much difficult sums like thermo ...
for waves, if we kno the basics, then it is enuf for jee ( i hope )

btw tnx vivek [1]
btw those asg are mostly selected irodov sums and some concept clearing sums ..wich u might encounter in standard books ...in short ... a collection of good sums