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Question
The figure shows a brick of weight 2 kgf and dimensions 20 cm × 10 cm × 5 cm placed in three different positions on the ground. Find the pressure exerted by the brick in each case.
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Solution
(a) Weight of bricks = Thrust = F = 2 kgf
Area of base = `20/100 xx 10/100 = 1/50 "m"^2`
Pressure exerted P = `"F"/"A" = "2 kgf"/(1/50 "m"^2) = 100 "kgf m"^-2`
Or
Area of base = area of top L × B
20 cm × 10 = 200 cm2
P = `"Thrust"/"A" = "2 kgf"/200 "cm"^2 = 1/100 = 0.01 "kgf cm"^-2`
(b)
area of base = area of top
= 5 cm × 10 cm = 50 cm2
Pressure exerted = P = `"F"/"A" = "2 kgf"/"50 cm"^2 = 0.04`
P = 0.04 kgf cm-2
(c)
Weight of brick
F = 2 kgf
Area of base = L × B
= 20 cm × 5 cm = 100 cm2
Pressure exerted = `"F"/"A" = 2/100 = 0.02 "kgf cm"^-2 `
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