A door, or a window, fills a hole in a wall. The wall above the hole is supported by a horizontal beam, called a lintel. Gravity exerts a force Mg on the mass, M, of the wall above the beam, where g is the acceleration due to gravity, as explained in post 16.16. Note that… Continue reading 21.17 Beams

This post is about equilibrium in statics – the title could cause confusion because the word “equilibrium” is used in science in several different contexts. In post 21.15 we saw that statics describes a system that is not moving in the frame of reference of an observer – it is in equilibrium. We also saw… Continue reading 21.16 Equilibrium