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

It works by applying force across the screws and the walls. Where the closer you are to the wall, the more the force is distributed across the wall and the screws. And each screw applied distributes that force from the equipment more evenly.

Kind of like a bed of nails. The more nails you have the more the weight is distributed. To the point each nail is taking up just a pound or less.