# Estimating the force of he water on the dutch boys finger

Nellen2222

## Homework Statement

The little dutch boy saved HOlland by sticking his finger in the leaking dike. if the water level was 2.5m above his finger, estimate the force of the water on his finger

## The Attempt at a Solution

I calculated the pressure on his finger by P = p0+pgh = 125,800 Pa.

But i have no idea what to do now.

Nessdude14
Pressure is Force/Area. You must estimate the area of the boy's finger and use this to convert the pressure to force.

Nellen2222
how do i do that..

Nessdude14
how do i do that..

Just look at the units:

$\displaystyle \frac{Force}{Area} × Area = Force$

To estimate the area of the boy's finger, I would just measure my own finger. Measure the diameter of your finger and approximate it as a circle.

Homework Helper
Gold Member
Nellen2222, Should you use absolute pressure or gauge pressure ρgh? (Edit: forget my question, I was thinking the question was asking what force the boy would need to exert to hold the water back.)

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