The density ratio of a and B is 2:1 and the side length ratio is 1:2. Place a in the center of B and place B on the horizontal table Find the ratio of the pressure of a to B and the pressure of B to the ground

The density ratio of a and B is 2:1 and the side length ratio is 1:2. Place a in the center of B and place B on the horizontal table Find the ratio of the pressure of a to B and the pressure of B to the ground

Let the density of a and B be 2p and P, and the side length be a and 2A
The pressure of a to B P1 = 2PA ^ 3G / A ^ 2 = 2pag
The pressure of B on the desktop P2 = 2PA ^ 3G + P (2a) ^ 3G / (2a) ^ 2 = 5pag / 2
P1/P2=2pag/(5pag/2)=4/5

The cube alloy block with length a on one side is composed of two metals with density P1 and P2. The pressure on the desktop is p. the volume ratio of the two metals in the alloy block is calculated

Let P1 be x and P2 be y, then x + y = a ^ 3, (xP1 + Yp2) g = PA ^ 2, and y = (PA ^ 2-p1ga ^ 3) / (p2g-p1g), then x / y + 1 = a ^ 3 / y,
x/y=ag(p2-p1)/(p-ap1g)

There is a rectangular iron block, 20cm long, 10cm wide and 5cm high. What is the mass of the rectangle?

Find the density of iron in the book, and then multiply the density by the volume to get the mass