how can i caculate the surface area of a galvanized washer, ignoring the outer and inner rims using diameter?

Question

I have the diameter of a galvanized washer coated in zink. I have to find the surface area of the washer, while ignoring the outer and inner side rims. I also have to find the volume but i do not have the height. I really need to know what i can do to solve this problem.

Onece i find the surface area, I have to find the volume, how can i do that with out knowing the hight? also does anyone know how i would caculate the relative uncerinty using the formula

relative uncert= (uncertinty) times (mesured value) times 100%

i am very lost on this entire problem, and i will not see my professor until wednessday

Answer 1

You need the inner radius as well. The area will be

Pi r(outer)^2 - Pi r(inner)^2

where r is radius, or diameter/2

For the volume you absolutely need the thickness. Just pile 2 washer on top of another and assume it is simply one double thickness washer. Volume is double because thickness is double.

Answer 2

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RE:
how can i caculate the surface area of a galvanized washer, ignoring the outer and inner rims using diameter?
I have the diameter of a galvanized washer coated in zink. I have to find the surface area of the washer, while ignoring the outer and inner side rims. I also have to find the volume but i do not have the height. I really need to know what i can do to solve this problem.

Answer 3

The area of a circle is calculated by using the formula Pi*R^2, or pi times the radius squared. Since you know the diameter of the entire washer and also know the diameter of the hole in the washer, you can use them to figure the surface area (without the rims).

Find the area of the circle as if it were a solid circle (Pi*R^2), then find the area of the smaller cirlce (the hole). Subtract the area of the smaller circle from the larger circle.

Now you have the surface area for one side of the washer. You must multiply this number by two since the washer is two sided. There you have your answer.


P.S. You cannot find the volume of the washer unless you have the height. It is not possible.

Answer 4

Surface Area Of A Washer

Answer 5

You haven't provided enough information to solve for the surface area of the washer. Further, you haven't said what kind of washer you are speaking of. Do you mean a washer like what is used with a bolt and nut or do you mean a washer like a clothes washer. If you are asking about a bolt washer, you need only to calculate the area of a circle using the outer diameter then subtract the area of the hole by finding its area using its diameter. To find the area of both sides of the washer, you then double the area of one side. If, on the other hand, you are talking about a clothes washer, you will need the depth of the washer tub as well as its diameter. You take the diameter of the tub, multiply by Pi (approx. 3.1416) and multiply this value by the depth of the tub to get the area of the inside of the tub. For the area of both the inside as well as the outside, you simply double the area of the inside of the tub. This ignores the slight difference of the two surface areas which would differ due to the thickness of the tub. This difference isn't sufficient to make any difference. Go get the depth of the tub and get to figuring.

Answer 6

Calculate the area of the whole washer (i.e. assume there is no hole in the middle). That is simple, area = pi*(diameter/2)^2. Recall that r = diameter/2. Now, find the area of the hole in the washer. For that you will need to know either the radius or diameter of the hole. Subtract the smaller area (hole) from the large area. This gives the area of one side of the washer. You'll need to multiply by 2 to go the area of both sides (or surfaces).

Answer 7

If you know what the washer is made of, and can find the density, all you need is mass to determine volume. You need the Outer diameter and the inner diameter of the washer to determine surface area.pi*OD*OD-pi*ID*ID will give you the surface area of one side. Double that since there are two sides.

Another way to measure volume is to weigh the washer in air, then weigh it under water. The difference is the amount of water displaced. Since water at sea level has a density of 1 g/cc, The difference in the weight in air and under water is also the volume of the washer.