# Homework Help: Normal Forces and Fluid Dynamics

1. May 8, 2012

### mtaniguchi

1.

A 5 kg board is arranged between 2 sawhorses (at right). If the board is in static equilibrium, what is the normal force on the board from sawhorse 2.

Link for the picture the question is referring to.
h.ttp://i.imgur.com/nBC6A.jpg

a. F2,normal = 0 N
b. F2,normal = 49.0 N
c. F2,normal = 36.8 N
d. F2,normal = 76.3 N
e. none of the above

2. This question refers to the same picture in question 1.

What is the normal force from sawhorse 1?

a. F1,normal = 0 N
b. F1,normal =12.3 N
c. F1,normal = 25 N
d. F1,normal = 50 N
e. None of the above

3.

For the pipe shown at right. If A1= 4A2, then…

Question is referring to this picture:
h.ttp://i.imgur.com/kDP93.jpg

a. v1=4v2
b. v1=¼v2
c. v1=¾v2
d. Not enough information

4.

When a person is holding a heavy object directly in front of them, they tend to lean back. Why?

a. It maintains a net force of zero
b. It maintains a net torque of zero

5.

Mechanic Bob has a hydraulic jack (as shown) that applies a maximum input force of Fin =4N. If the output piston is 3 times the area of the input piston (Aout=3Ain), what is the maximum weight Bob’s jack can lift?

Question refers to this picture:
h.ttp://i.imgur.com/NpZdb.jpg

a. 0 N
b. 1.33 N
c. 4 N
d. 12 N
e. None of the above

6.

(For the pipe at right) Water is flowing through the pipe’s left side with velocity v1=5 m/s and height y1=0 m and flowing out the right side with velocity v2=5 m/s at a height y2=2 m. What is the ΔP? (difference in pressure)

Question refers to this picture:
h.ttp://i.imgur.com/FnN59.jpg

a. 0 kPa
b. 9.8 kPa
c. 12.5 kPa
d. 19.6 kPa

Remove the . from the http to view the links.

Thanks.

2. May 8, 2012

Thanks.

3. May 8, 2012

### mtaniguchi

I tried doing the problems but I cant seem to get anywhere.

4. May 8, 2012

### Infinitum

How did you approach the first one? Where did you get stuck? Start with, what are the conditions for a body to stay in static equilibrium...

Last edited: May 8, 2012
5. May 8, 2012

### mtaniguchi

It's hard for me to understand the problem. I cant speak/read english very good.