The cube iron block with a mass of 7.9kg is placed on the horizontal table with an area of 0.5m2. What is the pressure on the horizontal table? V iron = m / ρ = 7.9kg/7.9 × 103kg / m3 = 0.001m3, so the side length of iron block is 0.1M, and the bottom area s = 0.01m2 So s = 0.01m2, P = mg / S = (7.9kg × 10N / kg) / 0.01m2 = 7900pa Because the area of the table is larger than the bottom area of the iron block, the contact area is the bottom area of the iron block

The cube iron block with a mass of 7.9kg is placed on the horizontal table with an area of 0.5m2. What is the pressure on the horizontal table? V iron = m / ρ = 7.9kg/7.9 × 103kg / m3 = 0.001m3, so the side length of iron block is 0.1M, and the bottom area s = 0.01m2 So s = 0.01m2, P = mg / S = (7.9kg × 10N / kg) / 0.01m2 = 7900pa Because the area of the table is larger than the bottom area of the iron block, the contact area is the bottom area of the iron block

You don't need to think about these words in the analysis, you just need to know that when calculating the pressure, the pressure is divided by the area under force
The stressed area refers to the area where the two parts contact each other. What you don't understand is to explain how to determine the "stressed area"
I can give an example: two objects, one with a large area and the other with a small area, then the part in contact with each other is the part with a small area. When calculating the stressed area, "take the small and medium area". The building owner understands?!
Hope to help the landlord

A cube iron block with a weight of 77.42n is placed in the center of a horizontal tabletop of 1 square meter. The tabletop is under the pressure of the iron block
The density of iron is 7.9 × 10 3 times kg / m3
thank you

V = 77.42 / (7900 * 10), square V to the third power, and get the contact area s. pressure P = f / s

A cube iron block with weight of 77.42n is still on a table with an area of 1m2, and the pressure on the table is calculated

According to the weight of the iron block, the mass of the iron block can be calculated. The iron density is 7.8kg/m3. In this way, the volume of the iron block can be calculated. Because it is a cube, the side length of the iron block can also be calculated. The area of one side of the cube can be calculated. Compared with the area of the table top, if the area of the table top is larger than the area of the bottom of the iron block, the s of the pressure is the area of the bottom of the iron block, such as the area of the table top is smaller than the area of the bottom of the iron block, Then s of pressure is the area of tabletop, f is 77.42n