What pressure does a four-axle car weighing 30 tons exert on the rails if the contact area

What pressure does a four-axle car weighing 30 tons exert on the rails if the contact area of each wheel with the rail is 4 cm²?

n = 4.

m = 30 t = 30,000 kg.

g = 10 N / kg.

S1 = 4 cm2 = 4 * 10 ^ -4 m2.

P -?

To determine the pressure of the car on the rails P, it is necessary to divide the force F with which it presses on the rails by the area S of the contact between the car and the rails: P = F / S.

Since the car has n = 4 wheels, the area of contact between the car and the rails will be S expressed by the formula: S = n * S1.

The car presses on the rails by the force of its weight: F = m * g.

The pressure of the car will be expressed by the formula: P = m * g / n * S1.

P = 30,000 kg * 10 N / kg / 4 * 4 * 10 ^ -4 m2 = 18.75 * 10 ^ 7 Pa.

Answer: the pressure of the car on the rails is P = 18.75 * 10 ^ 7 Pa.