Because we grew up in a pressurized system, our bodies have developed so that al

Question

Because we grew up in a pressurized system, our bodies have developed so that all pressures interior to our body are relatively close to atmospheric pressure. With small pressure differentials, we have a difficult time gauging the magnitude of atmospheric pressure. Consider a person lying on his stomach, with sheets of paper stacked on his back. If each sheet of paper has a mass of 0.00410 kg and is the standard letter size 8.5" × 11" (0.216 m × 0.279 m), how many sheets would stack to produce a pressure on his back equal to atmospheric pressure (roughly 101325 Pa)?

Explanation / Answer

We know that the pressure = Force / area
so area of the sheet is = 0.216*0.279 = 0.060264 m2
Force = mass*acceleration due to gravity
So let us consider that N sheet able to produce required pressure
so total force by n sheets = nMg where M is mass of sheet , g is the acceleration due to gravity.
Force = n*0.0041*9.81 = (0.040221 n ) newtons
So pressure is 101325 = Force /area
101325 = (0.040221 n)/0.060264
n = 151817.45
so approx it will be 151818

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