# Homework Help: Determine the speed at which the water leaves the hole

1. Nov 8, 2007

### Sunsing

1. The problem statement, all variables and given/known data

A large storage tank, open to the atmosphere at the top and filled with water, develops a small hole in its side at a point 15.0 m below the water level. If the rate of flow from the leak is 2.10x10-3 m3/min

(a) Determine the speed at which the water leaves the hole. =17.15m/s

(b) Determine the diameter of the hole. = ?

2. Relevant equations

F=eta(Av/d)

I'm not sure what equation to use for this.

3. The attempt at a solution

I'm just not sure how to start this.
Any suggestions?

2. Nov 9, 2007

### stewartcs

The volumeteric flow rate is given by Q = Av.

You are given Q and you have apparently found v (the velocity), so just solve for A (the area) and then calculate the diameter.

3. Nov 9, 2007

### catkin

a) Conservation of energy. The pressure energy of the water just inside the hole is equal to the kinetic energy of the water just outside the hole. See Bernoulli for terms in the equation.

b) I think it is acceptable (= a good approximation) to assume constant velocity accross the whole are of the whole so stewartcs' formula applies.