# Explanation for hydrodynamic problem

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1. Jan 9, 2017

### Mohamed Essam

• New member advised that an attempt at a solution is required for all homework help requests.
1. The problem statement, all variables and given/known data
See the photo of the problem in the attachment

2. Relevant equations
Bernoulli equation and continuity equation

3. The attempt at a solution
I don't know from where to begin , i only can get the velocity of fluid when it reaches the hole

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Last edited: Jan 9, 2017
2. Jan 9, 2017

### haruspex

You must have been taught something on the topic. Any standard equations relating to fluid flow?

3. Jan 9, 2017

### Mohamed Essam

Yeah , bernoulli equation and continuity equation.

4. Jan 9, 2017

### haruspex

You should have listed those under Relevant Equations in the template.
So try applying Bernoulli's. What do you get?

5. Jan 9, 2017

### Mohamed Essam

Only the velocity of fluid at the hole , i don't know what to do i don't know any other information of how to get the distance x that the fluid will cover

6. Jan 9, 2017

### haruspex

That's a good start. (Next time, please show how far you got in your initial post, otherwise you risk having your post deleted.)
If you throw an object horizontally at a known speed and known height, can you figure out where it will land?

7. Jan 9, 2017

### Mohamed Essam

I think it's by laws of motion !

8. Jan 9, 2017

### haruspex

Yes, specifically, motion under constant acceleration. What equations do you know for that?

9. Jan 9, 2017

### Mohamed Essam

D=Vot+1/2at^2

10. Jan 9, 2017

### haruspex

Right. How can you apply that here?

11. Jan 9, 2017

### Mohamed Essam

That the problem I've faced , i don't know how to apply it here

12. Jan 9, 2017

### haruspex

What facts do you know in this problem regarding speeds, time, distances and accelerations?

13. Jan 9, 2017

### Mohamed Essam

I only know the distance from the hole to ground y is 30 cm and the velocity of fluid when it reaches the hole , i only don't know the time when it reaches ground and the acceleration of fluid .

14. Jan 9, 2017

### haruspex

What is causing it to accelerate, once it has left the tank?

15. Jan 9, 2017

### Mohamed Essam

Only gravity i think

16. Jan 9, 2017

### haruspex

Right, so you know the vertical and horizontal (0) accelerations.
Apply your equation for both directions.

17. Jan 9, 2017

### Mohamed Essam

So i can get the time from the y-direction equation and put it in the x-direction equation so i can get the distance x , is that right ?!

18. Jan 10, 2017

### haruspex

Right!

19. Jan 10, 2017

### Mohamed Essam

But why you assumed that the horizontal acceleration = 0 , if i didn't know that it equals 0 i can't solve it , so i need to understand why it equals 0

20. Jan 10, 2017

### haruspex

What force is there to accelerate it horizontally?