A lead brick, 5.0 12.0 22.0 cm, rests on the ground on its smallest face. What p
ID: 2068293 • Letter: A
Question
A lead brick, 5.0 12.0 22.0 cm, rests on the ground on its smallest face. What pressure does it exert on the ground? (Lead has a density of 11.8 g/cm3.)kPa
In a tornado, the pressure can be 15% below normal atmospheric pressure. Sometimes a tornado can move so quickly that this pressure drop can occur in one second. Suppose a tornado suddenly occurred outside your front door, which is 192 cm high and 99 cm wide. What net force would be exerted on the door?
NIn what direction would the force be exerted?
Explanation / Answer
Weight of brick = Density*volume*gravity = (11.8/1000)*(5*12*22)*9.81 = 152.8 N
Pressure = Force/Area = 152.8/(5*12*10-4) = 25466.7 Pa
Assume atmospheric pressure = 101325 Pa
Pressure in tornado = 101325 - 0.15*101325 = 86126 Pa
force = pressure*area
= 86126*(192*99)*10-4 = 163.7 kN
This force will act normal to the door.