Water is flowing at a speed of 1.5 ms-1 through a horizontal tube of cross-sectional area 10-2m2 and you are trying to stop the flow by your palm. Assuming that the water stops immediately after hitting the palm, the minimum force that you must exert should be (density of water = 103 kgm-3).

Question

Water is flowing at a speed of 1.5 ms-1 through a horizontal tube of cross-sectional area 10-2m2 and you are trying to stop the flow by your palm. Assuming that the water stops immediately after hitting the palm, the minimum force that you must exert should be (density of water = 103 kgm-3). (A) 15 N (B) 22.5 N (C) 33.7 N (D) 45 N

Tardigrade Admin · Accepted Answer

F=v (dm/dt) =v Apv =v2Apv =(1.5)2×10-2× 103 =2.25× 10=22.5 N

Q. Water is flowing at a speed of 1.5ms−1 through a horizontal tube of cross-sectional area 10−2m2 and you are trying to stop the flow by your palm. Assuming that the water stops immediately after hitting the palm, the minimum force that you must exert should be (density of water = 103kgm−3).

15 N

22.5 N

33.7 N

45 N

F=vdtdm​ =vApv =v2Apv =(1.5)2×10−2×103 =2.25×10=22.5N

$F = v \frac{d m}{d t}$
$= v A p v$
$= v^{2} A p v$
$= (1.5)^{2} \times 1 0^{- 2} \times 1 0^{3}$
$= 2.25 \times 10 = 22.5 N$