Q-1 : A bodu weighs 8 gm when placed in one pan and 18 when placed on a other pan of a false balance . If the beam is horizontal when both the pans are empty , the true weight of the body is
Q-2 : when one swims across a river max. energy is spent in second 1/3 of the distance why ?
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2 Answers
62Solve the first part like this..
L and L' are the lengths of the two beams ...
M and M' are the masses of the pans alone.
thus,
LM=L' M'
also,
L(8+M)=L'(x+M')
L(x+M)=L'(18+M')
MM'=8+Mx+M'=x+M18+M'
Now solve for x
:)
62Q2 is a good question... THis has to do with boundary condition...
See the speed of river is maximum at the center and lesser at the banks.. (This comes from the fact that at the surface, or just on the shore of the river.. the velocity of water is zero....)
