What pressure does a boy weighing 42 kg produce on the floor, and he lives on his shoulders a load of 5 kg

What pressure does a boy weighing 42 kg produce on the floor, and he lives on his shoulders a load of 5 kg, if the area of each sole of his shoes is 0.01 m2.

mm = 42 kg.

mg = 5 kg.

g = 10 N / kg.

S1 = 0.01m2.

N = 2.

P -?

To find the pressure of a boy with a load on the surface of the earth P, it is necessary to divide the force F with which he presses on the surface of the floor by the area of ​​their contact S: P = F / S.

Since the boy has a mass mm and on his shoulders holds a load of mass mg, he acts on the surface of the floor by the force of the boy’s weight with a load, the value of which is expressed by the formula: F = (mm + mg) * g, where g is the acceleration of gravity.

Since the boy stands on two legs N = 2, then the area S, on which his weight with the load acts, is expressed by the product: S = N * S1, where S1 is the area of ​​one shoe sole.

The boy’s pressure with a load P will be determined by the formula: P = (mm + mg) * g / N * S1.

P = (42 kg + 5 kg) * 10 N / kg / 2 * 0.01m2 = 23500 Pa.

Answer: the pressure of the boy with the load on the floor is P = 23500 Pa.