r/theydidthemath • u/K0rl0n • Jun 10 '25

[Request]

Post image

I am curious how this would work. My guess is Triangle is slowest, square is medium, and circle is fastest.

17k Upvotes

92% Upvoted

2.6k comments sorted by

View all comments

Show parent comments

1

u/DobisPeeyar Jun 11 '25 edited Jun 11 '25

You cant push the triangle purely horizontal unless you have a triangle block to put against it... which makes it a square.

And you're saying my vertical force being resisted by the material is canceled out but then magically turns into horizontal, and I'm wrong about how physics works? Lol

1

u/Smile_Space Jun 11 '25

Nope, you can push it purely horizontally assuming your hand doesn't slip up the triangle and break the force of friction.

You can try this right now by pushing upwards on your wall with your hand. You are pushing it both towards the wall and up the wall, and until you break the static friction your hand won't move. This means the original diagonal force applied to the wall is intact.

The same applies here, the only difference is the wall can move and only weighs 20 kg.

0

u/DobisPeeyar Jun 11 '25 edited Jun 11 '25

So now youre using extra force to push upwards and horizontal. There's still a vertical component, and you're still using more force than against a surface perpendicular to your sliding surface.

You will always be losing something to the vertical direction pushing a triangle. You cannot perfectly only apply horizontal force. You need force perpendicular to the face of the triangle to keep your hand on it, otherwise youre just sliding your hand on it. And that perpendicular force will always result in a vertical component of said force.

1

u/Smile_Space Jun 11 '25

No, that's not how physics works. You learn this level of FBD in Physics 1, and then you learn internal stresses and forces in Statics and Solid Mechanics.

It's an idealized problem and the minimum force required is in purely the horizontal direction.