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

[xerxies]

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

 

[MarkFL]

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:

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

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

$$\rho\equiv\frac{w}{V}\implies w=\rho V$$

For water, we have:

$$\rho\approx 62.3\frac{\text{lb.}}{\text{ft}^3}$$

Can you proceed?

 

[xerxies]

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:

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

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

$$\rho\equiv\frac{w}{V}\implies w=\rho V$$

For water, we have:

$$\rho\approx 62.3\frac{\text{lb.}}{\text{ft}^3}$$

Can you proceed?

sorry i only have very limited schooling and need final answer as total wieght thanks so much

 

[SuperSonic4]

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

 

[xerxies]

thanks all who helped