Momentum

the second plank will have momentum of (M+m)v
the first plank will have momentum of -Mv

I am getting final velocity of the plank on right as m²v/M(m+M).
Please verify if it is correct. I shall post the solution only then
I like your dog very much. Which species does it belong to? [4]

:P I don't have answers, Only question. BTW, I solved it too, but because of lack of answers, I need to confirm.

Asish bro...
I think there is one mistake--
Even I got the same till here
"Initial jump from left plank
Pi = 0
Pfdog = mv (i)
So, vfplank = -mv/M (i)

Dog reaching second plank
Pi = mv (i)
Pf = (M+m)v'
=> v' = mv/(M+m) i"

Now,
Dog jumps from second plank
Pi = mv (i)
Pfdog = -mv (i)
vfplank = 2mv/M (i)

Here you are not considering the initial momentum of the plank which is
mv/(M+m) towards right w.r.t ground.

Here you are not considering the initial momentum of the plank which is
mv/(M+m) towards right w.r.t ground.

But Why.. during the second jump the velocity of the second plank should have increased more na.

@Khyati

Kitni mehnat se banaya tha... Daar raha tha kahi 5 pair na ban jaye! :)

During the second jump,
Treating dog and plank as our system,
Pi(dog) + Pi(plank) = Pf(dog) + Pf(plank)
m(mv/M+m) + M(mv/M+m) = -mv + Mv1

I think it should be done this way.