Calculating Pressure for a Moving Part: 285 RPMs on a 4 Inch Cylinder

  • Thread starter RanMan
  • Start date
  • Tags
    Force
In summary, to calculate the force on a 1/2 oz moving part spinning at 285 rpms around a 4 inch cylinder, you will need to convert the mass from ounces to slugs and determine the velocity from the radius and rpm. Then, use the formula F= Mv²/r to calculate the force in pounds.
  • #1
RanMan
I am currently try to figure out the amount of pressure on a moving part that weights about an 1/2 oz. It spins at a rate of 285 rpms around the outside of a 4 inch cylinder.
I'm sure there has to be a formula of some sort that can assist in this calculation. Thanks for any help you may be able to give.

Thanks,
RanMan
www.prewettmills.com[/URL]
 
Last edited by a moderator:
Physics news on Phys.org
  • #2
F= Mv²/r

where M is the mass of the object,

v is it's velocity

r the radius

You'll have to convert oz to mass units and find the object's velocity from the radius and rpm.
 
  • #3
Janus, I appoligize for the detailed questions but I know absolutely nothing about physics.
I do not know how to determine the velocity nor do I know how to convert ounces to mass. I'm sorry for not knowing a thing about physics.
All I know is the information that i need which is the force.

Thanks,
RanMan
www.prewettmills.com[/URL]
 
Last edited by a moderator:
  • #4
Well the unit of mass in the FPS system is the slug, and a one slug mass would weigh 32.175 lbs, and there are 16 ounces to a lb.

so mass = 1/(32.175x16)/2 = .0009625 slug.

The circumfernce of a circle of radius 4 in. is 2*4* pi = 25.13 in. or 2.094 ft.

This is the distance the object travels in one revolution. it does this 285 times per min, so its velocity is 2.094*285 = 596.79 ft/min.

divide this by 60 to get ft/sec for 9.9465 ft/sec and you have v

thus
r = .33333 ft
M= .0009625 slugs
v= 9.9465 ft/sec

plug them into the formula, and you'll get the force in pounds.
 

1. How do you calculate pressure for a moving part?

To calculate the pressure for a moving part, you need to know the rotational speed (in rpm) and the size of the cylinder (in inches). You can use the formula P = (0.000019 * N * D^2), where P is pressure in psi, N is rotational speed in rpm, and D is the diameter of the cylinder in inches. In this case, the formula would be P = (0.000019 * 285 * 4^2) = 10.8 psi.

2. What is the relationship between rpm and pressure?

The relationship between rpm and pressure is direct. As the rotational speed increases, the pressure also increases. This is because the faster the cylinder moves, the more force it exerts on the surrounding air, resulting in higher pressure.

3. How does the size of the cylinder affect the pressure?

The size of the cylinder directly affects the pressure. As the diameter of the cylinder increases, the pressure also increases. This is because a larger cylinder has a larger surface area, resulting in more force being exerted on the surrounding air.

4. What is the unit of measurement for pressure in this calculation?

The unit of measurement for pressure in this calculation is pounds per square inch (psi). This is a commonly used unit for measuring pressure in the United States.

5. Can this calculation be used for any type of moving part?

Yes, this calculation can be used for any type of moving part as long as you have the necessary information: the rotational speed and the size of the cylinder. However, it is important to note that the formula may differ depending on the units of measurement used (e.g. metric vs. imperial).

Similar threads

  • Other Physics Topics
Replies
6
Views
2K
Replies
3
Views
1K
Replies
28
Views
1K
Replies
7
Views
700
  • General Engineering
Replies
15
Views
652
Replies
3
Views
1K
Replies
3
Views
319
  • Mechanical Engineering
Replies
6
Views
414
  • Engineering and Comp Sci Homework Help
Replies
4
Views
1K
Replies
24
Views
2K
Back
Top