 #1
 160
 8
 Homework Statement:
 To Calculate Force of Water Acting On A Full Tank Of Water
 Relevant Equations:

Pressure = Density * Gravity * Depth Below Water Surface
Pressure = Force / Area
Hello Community
I was hoping someone could me with the following question:
A rectangular tank contains water.
It is 12m long, 4m wide and has a height of 3m.
If the tank is full determine:
1) The Force on the long side
2) The Force on the short side
3) The moment at the bottom of the long side and its centre.
I am just tying to figure out part 1 for now.
Trying to visualise the problem I would say that the area of the long side of the tank wall is 12m * 3m = 36m^2, and the question is asking how much force is the water exerting on this wall.
I know/worked out the following:
 Water Density = 1000kg/m^3
 Pressure = Density * Gravity * Depth Below Water Surface
 Pressure = Force / Area
 The total volume of the water in the tank is 12 * 4 * 3 = 144.
 Using the equation Density = Mass/Volume, I can say that 1000 = Mass/144, by rearranging I get Mass to equal 144000kg.
I don't really know where to go from here, I have been told that the answer is 529.2kN  but I want to know how to get to the answer.
I am struggling because I know pressure increases with depth so my gut feeling is that some form of integration is needed but I have been told that integration can be used but is not needed.
Can someone help?
Thank you.
I was hoping someone could me with the following question:
A rectangular tank contains water.
It is 12m long, 4m wide and has a height of 3m.
If the tank is full determine:
1) The Force on the long side
2) The Force on the short side
3) The moment at the bottom of the long side and its centre.
I am just tying to figure out part 1 for now.
Trying to visualise the problem I would say that the area of the long side of the tank wall is 12m * 3m = 36m^2, and the question is asking how much force is the water exerting on this wall.
I know/worked out the following:
 Water Density = 1000kg/m^3
 Pressure = Density * Gravity * Depth Below Water Surface
 Pressure = Force / Area
 The total volume of the water in the tank is 12 * 4 * 3 = 144.
 Using the equation Density = Mass/Volume, I can say that 1000 = Mass/144, by rearranging I get Mass to equal 144000kg.
I don't really know where to go from here, I have been told that the answer is 529.2kN  but I want to know how to get to the answer.
I am struggling because I know pressure increases with depth so my gut feeling is that some form of integration is needed but I have been told that integration can be used but is not needed.
Can someone help?
Thank you.