(see fluids in the news article titled "walking on water ," section 1.9 .) (a) the water strider bug shown in fig. p1.131 is supported on the surface of a pond by surface tension acting along the interface between the water and the bug's legs. determine the minimum length of this interface needed to support the bug. assume the bug weighs 1 × 10-4 n and the surface tension force acts vertically upwards. (b) repeat part (a) if surface tension were to support a person weighing 640 n.

Respuesta :

Part a)

Surface tension of water

[tex]S = 72 * 10^{-3} N/m[/tex]

Weight of the bug is

[tex]W = 1 * 10^{-4} N[/tex]

now we can say

[tex]F = S*L[/tex]

[tex]1*10^{-4} = 72 * 10^{-3} * L[/tex]

L = 1.39 mm

Part b)

Now if the same surface is to balance a man of weight 640 N

Now by same formula

[tex]F = S*L[/tex]

[tex]640 = 72*10^{-3} * L[/tex]

[tex]L = 8.89 * 10^3 m[/tex]