Topic 5 - 5.4 Harder questions on Pressure

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Collins, p.107, Q.4.

Q4)

Ordinary Shoe heel: 

Area: 0.0025m^2

Mass: 40x10 = 400N

Pressure = Force / Area

Pressure = 400 / 0.0025

Pressure = 160,000 N/m^2

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Elephant:

Area = πx0.1x0.1

Mass = 40x10 = 400N

Pressure = Force / Area

Pressure = 5000 / ( πx0.1x0.1)

Pressure = 160,000 N/m^2 (2 s.f.)

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High-heeled shoe:

Area = 0.5/10,000

Mass = 400

Pressure = Force / Area

Pressure = 400 / (0.5/10000)

Pressure = 8,000,000 N/m^2

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The high-heeled shoe will damage a wooden floor that starts to yield at a pressure of 4000 kPa (4000 x 1000 = 4,000,000 N/m^2).