Which of the bodies produces the least pressure on the ground: a car weighing 1400 kg, a tank weighing 34 tons, or a person weighing 90 kg. The support area is respectively equal: 500cm2, 40000cm2 and 100cm2.
mа = 1400 kg.
mt = 34 t = 3400 kg.
mh = 90 kg.
g = 10 N / kg.
Sa = 500 cm2 = 0.05 m2.
St = 40,000 cm2 = 4 m2.
Sч = 100 cm2 = 0.01 m2.
The pressure of a body on the surface of the soil P is the ratio of the force F with which this body acts on the area of contact of these bodies S: P = F / S.
All bodies act on the surface by the force of their weight: F = m * g
Pa = ma * g / Sа.
Ra = 1400 kg * 10 N / kg / 0.05 m2 = 280,000 Pa.
Pt = mt * g / St.
Рт = 34000 kg * 10 N / kg / 4 m2 = 85000 Pa.
Ph = mh * g / Sh.
Rh = 90 kg * 10 N / kg / 0.01 m2 = 90,000 Pa.
Answer: the least pressure on the ground is produced by the tank P = 85000 Pa.
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