How can screwing a massively heavy object to a wall with four screws (like a water tank) be safe? I feel its always going to fall, taking a piece of the wall with it.

Question

Or screwing workout equipment which you constantly pull with your own weight.

EDIT: Forgot to add, I’m not in the US, I’m talking about brick or concrete walls, not drywalls. Although probably the basic principle applies when it comes to explaining how force works.

In: Physics

Answer 1

You dont normally use normal screws for stuff like that either heavy duty screws into something like a stud that can support a lot of weight or something like toggle bolts which are actually pretty clever. They spead out behind the drywall once inserted and spread the force of the weight out along a greater area of wall rather than a single spot. Basically taking advantage of physics. You can drastically increased the amount of weight a wall can support that way as well.