- #1
Hyperreality
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- 0
A peron on a boat with a total mass of M are stationary in the river, the man throws his shoes mass m at a velocity v successive, find the expression for the boat's final velocity.
Here is what I did.
First let u be the velocit of the boat
After the first shoes:
(M + m)u = mv
u = mv(1/(M +m))
After the second shoes:
Change in momentum of the boat = Change in momentum of the shoe
So, Mu'- (M + m)u = mv, but (M + m)u = mv
Therefore Mu' = 2mv and u' = 2mv/M
u + u' = mv(2/M + 1/(M + m)) is the final velocity of the boat.
But the correct answer is mv(1/(M + m) + 1/(M + 2m)), can anyone please tell me where I've got it wrong?
Here is what I did.
First let u be the velocit of the boat
After the first shoes:
(M + m)u = mv
u = mv(1/(M +m))
After the second shoes:
Change in momentum of the boat = Change in momentum of the shoe
So, Mu'- (M + m)u = mv, but (M + m)u = mv
Therefore Mu' = 2mv and u' = 2mv/M
u + u' = mv(2/M + 1/(M + m)) is the final velocity of the boat.
But the correct answer is mv(1/(M + m) + 1/(M + 2m)), can anyone please tell me where I've got it wrong?