Pressure is important in a range of everyday situations.
A metal box is 60 cm long, 20 cm wide and 50 cm tall.
It has a mass of 30 kg. Find the maximum pressure which the box can exert on the top of a table.
The maximum pressure will occur when the face with minimum area is in contact with the table
The face with minimum area has dimensions 20 cm by 50 cm.
Area = 20 cm x 50 cm.
A = 1 000 cm2.
Force on the bench = weight of the box = mg.
Force = 30 kg x 10 N/kg.
Force F = 300 N.
p = 0.3 N/cm2
The maximum pressure exerted by the box is 0.3 N/cm2.
A girl standing on one foot exerts a pressure of 6 N/cm2 on the ground. If the area of her foot is 75 cm2, calculate the downward force.
F = pA.
p = 6 N/cm2
A = 75 cm2
P = 6 N/cm2 x 75 cm2
P = 450 N.
The downward force exerted by the girl is 450 N