Question

A vertical rectangular wall with a width of 20 m and a height of 12 m is holding a 7-m-deep water body. The resultant hydrostatic force acting on this wall is (a) 1370 kN (b) 4807 kN (c) 8240 kN (d) 9740 kN (e) 11,670 kN

Answer 1

The resultant hydrostatic force acting on the vertical rectangular wall is 1370 kN.

Step-by-step explanation:

To calculate the resultant hydrostatic force acting on the vertical rectangular wall, we need to determine the pressure exerted by the water and then find the force using the formula force = pressure x area.

The pressure exerted by the water can be calculated using the formula pressure = density x gravity x height, where density of water is approximately 1000 kg/m³ and gravity is approximately 9.8 m/s².

The area of the wall can be determined by multiplying its width and height. Plugging these values into the formula, we find that the resultant hydrostatic force acting on the wall is 1370 kN.

Answer 2

(c) 8240 kN

Resultant hydrostatic force F = 8240 kN

Step-by-step explanation:

Force can be expressed as;

F = ma

F = mg ......1

Where,

F = force

m = mass

a = acceleration

g = acceleration due to gravity

And we know that mass of an object is the product of

Density and Volume

m = pV

And volume V = area × height = Ah

m = pAh .....2

Substituting m into equation 1

F = pAhg = pghA ......3

Given;

Density of water p = 1000kg/m^3

g = 9.81m/s^2

Area A = 20m × 12m = 240m^2

h = depth/2 = 7/2 = 3.5m

Substituting the values into equation 3, we have;

F = 1000×9.81×3.5×240

F = 8240400 N

Resultant hydrostatic force F = 8240 kN