Question

A solid concrete block weighs 210 N and is resting on the ground. Its dimensions are 0.410 m x 0.200 m x 0.0720 m. A number of identical blocks are stacked on top of this one. What is the smallest number of whole bricks (including the one on the ground) that can be stacked so that their weight creates a pressure of at least two atmospheres on the ground beneath the first block? (Hint: First decide which face of the brick is in contact with the ground.)

Answer 1

Use the smallest area "face"
0.1 x 0.2 = 0.02 m^2

Pressure = Force / Area

101000 . 0.02 = Force = 2020 N

Number of blocks = 2020 / 174 = 11.6

So 12 blocks are needed to produce a pressure of at least one atmosphere.

Answer 2