# Fluid in hypodermic needle

1. Nov 18, 2007

### Paulbird20

What force on the plunger would be needed to push fluid into a vein where the gauge pressure is 18 mm Hg? Answer for the instant just before the fluid starts to move.

I know i need the density of mercury (in Meters) and that equals = 13.534e-3 / 100 which is

1.3534e-4 for the density

Next i did the conversion of the atm pressure of mercury and got 133 n / m2. (i think thats correct)

ok so i know i need to use pascals and i developed my equations i was given and ended with

F1 = P1/ A1

Which is

Density mercury * atm pressure mercury * 9.8 / pie * D^2

I think that is the correct equation and when i use it i get the wrong answer.

What im really stuck with is what i use as the diameter.

Any help would be great if i messed up any conversions and what not. TY

2. Nov 18, 2007

### Paulbird20

bumb

3. Nov 18, 2007

### Paulbird20

bumb

4. Nov 18, 2007

### Paulbird20

bump^3

5. Nov 18, 2007

### Paulbird20

anyone?

6. Nov 18, 2007

### Paulbird20

last attempt..

7. Nov 18, 2007

### Paulbird20

sad panda

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