Physics (AS & A Level) · May / June 2020 · Paper 13 · Question 20

The diagram shows a simplified model of a building with four identical heavy floors. The spacing of the bottom floor from the ground is twice that of the spacing between the floors. Between each floor are equal numbers of vertical steel supporting rods of negligible mass compared with the floors. The rods are of different diameters so that the stress in each rod is the same. What is the ratio $\dfrac{\text{diameter of bottom rods}}{\text{diameter of top rods}}$?

1. A2
2. B4
3. C8
4. D16

As printed in the paper