Weight of Water on 180ft x 40ft Roof: Help Needed!

In summary: Technically your figures are for the mass of water and not its weight although the two are used interchangeably. If you need to find the force of the water then let us knowthanks all who helped me as i was stuck on this problem for a whilenow doing it the right way thanks!
  • #1
xerxies
3
0
hopeing some one can help me...180ft x 40 ft x 2 inches of water ...what is weight of water on roof thanks to all who ponder this as i am sadly in need of help...should have stayed in school lol thanks again people...xerxies
 
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  • #2
First, we need to find the volume of the water. The volume of a cuboid is simply the product of its length, width, and height:

\(\displaystyle V=\left(180\text{ ft}\right)\left(40\text{ ft}\right)\left(2\text{ in}\cdot\frac{1\text{ ft}}{12\text{ in}}\right)=1200\text{ ft}^3\)

Now, weight density $\rho$ is defined as follows (where $w$ is weight):

\(\displaystyle \rho\equiv\frac{w}{V}\implies w=\rho V\)

For water, we have:

\(\displaystyle \rho\approx 62.3\frac{\text{lb.}}{\text{ft}^3}\)

Can you proceed?
 
  • #3
MarkFL said:
First, we need to find the volume of the water. The volume of a cuboid is simply the product of its length, width, and height:

\(\displaystyle V=\left(180\text{ ft}\right)\left(40\text{ ft}\right)\left(2\text{ in}\cdot\frac{1\text{ ft}}{12\text{ in}}\right)=1200\text{ ft}^3\)

Now, weight density $\rho$ is defined as follows (where $w$ is weight):

\(\displaystyle \rho\equiv\frac{w}{V}\implies w=\rho V\)

For water, we have:

\(\displaystyle \rho\approx 62.3\frac{\text{lb.}}{\text{ft}^3}\)

Can you proceed?
sorry i only have very limited schooling and need final answer as total wieght thanks so much
 
  • #4
xerxies said:
sorry i only have very limited schooling and need final answer as total wieght thanks so much

Hello xerxies, MHB is a board which aims to help you find the answer by yourself. We could give you the answer but it wouldn't help if this came up again in future.

Mark has given you the total volume as 1200 ft³, the density 62.3 lb/ft³ and the formula for weight weight = volume * density

Thus to find the weight multiply 1200 ft³ x 62.3 lb/ft³

edit: Technically your figures are for the mass of water and not its weight although the two are used interchangeably. If you need to find the force of the water then let us know
 
  • #5
thanks all who helped
 

FAQ: Weight of Water on 180ft x 40ft Roof: Help Needed!

How do I calculate the weight of water on a 180ft x 40ft roof?

The weight of water on a roof can be calculated by multiplying the area of the roof (180ft x 40ft = 7,200 ft2) by the weight of water per square foot, which is 5.2 pounds. This results in a total weight of 37,440 pounds or 18.72 tons.

Is the weight of water on a roof evenly distributed?

No, the weight of water on a roof is not evenly distributed. The majority of the weight is concentrated in the center of the roof, with the weight gradually decreasing towards the edges.

Does the pitch of the roof affect the weight of water?

Yes, the pitch of the roof can affect the weight of water. A steeper pitch will allow the water to run off more easily, reducing the weight on the roof. However, a flatter pitch may cause the water to accumulate and increase the weight on the roof.

How does the weight of water on a roof impact the structural integrity?

The weight of water on a roof can put additional stress on the structure, especially in areas where the roof is weak or damaged. This can potentially lead to structural damage or collapse if the weight exceeds the load-bearing capacity of the roof.

What precautions should be taken to prevent damage from the weight of water on a roof?

To prevent damage from the weight of water on a roof, it is important to regularly inspect and maintain the roof to ensure it is in good condition. Additionally, it is important to have proper drainage systems in place to prevent water from accumulating on the roof. In areas with heavy rainfall, it may also be necessary to reinforce the roof to withstand the weight of water.

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