A) Increase of 12.5 gm-wt
B) Increase of 6.25 gm-wt
C) Decrease of 12.5 gm-wt
D) Decrease of 6.25 gm-wt
Correct Answer: C
Solution :
Let A = The area of cross section of the hole v = Initial velocity of efflux d = Density of water, Initial volume of water flowing out per second = Av Initial mass of water flowing out per second = Avd Rate of change of momentum = Adv2 Initial downward force on the flowing out water = Adv2 So equal amount of reaction acts upwards on the cylinder. \ Initial upward reaction =\[Ad{{v}^{2}}\] [As \[v=\sqrt{2gh}\]] \[\therefore \] Initial decrease in weight \[=Ad\,(2gh)\] \[=2Adgh\]\[=2\times \left( \frac{1}{4} \right)\times 1\times 980\times 25=12.5\] gm-wt.You need to login to perform this action.
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