/sci/ - Science & Math

because grip

coefficient of friction I'd assume
the rubber band bottle has a higher mew between both the bottle and your hand

Greater friction, lower force needed. 9th grade physics.

>>3920025
>>3920029
>>3920030
Derp detected, he said his hands are not slipping.

It's actually because the cap suddenly becomes wider. The higher radius allows you to apply more torque with the same applied force.

>>3920029

What makes rubber have such a high static friction force?

(am I saying that right? :P)

>>3920050

That might be A PART of it. You know those huge 3-liter soda bottles with the wider caps? Always easy to open. But if what you are saying is correct, I could use basically any material to widen the cap and it'd be easier to open. And that isnt the case.

You have more torque with a larger radius from the center of the cap.

>>3920072
>>3920050
Lolno. The extra distance is next to nothing.
The reason is indeed extra grip.
Most of your effort goes into preventing your hand from slipping. By applying more inward force, you increase the friction.
If you use a rubber band, you don't need to use all your force to prevent your hand from slipping, and you can use all your force to actually open the cap.

Your hands may not slip, you still have to push harder on the cap in order prevent slipping than you have with a rubber band.

>>3920098

Seems to make the most sense.

You sir, win :D

Most bottle caps have ridges that decrease the contact surface area between your hand and the cap. The rubber band is pretty smooth so you can apply more force to actually turn the cap.

>>3920019
You only think your hands arent slipping, OP.

>>3920129

Yeah.

>>3920019
>>I tie a rubber band around the cap of the bottle.

3 cases:
1) I assume you form a lever? In that case it's easy, due

2)I assume you just form a new layer around the cap. In that case, your friction coefficient changed. Even if you didn't notice it first if you just use your hand.

3)You tried that in a series, first you tried with the hand alone, then with the rubberband. You actually invested some work to open the bottle already during the first, though it's hard to trace. You may try that with other objects that have these caps to open up: First try it with your hand, then rest. Then, try it again. Rest again. After that, you should be able to open it at the third try.

>>3920196
mfw 3rd

It's all about grip strength. If you have bigger, stronger hands you'll never have problems opening things.

Without the rubber band, you can't squeeze hard enough that you could turn the cap without slipping. You don't have enough grip strength.

With the rubber band, you don't need to squeeze as hard to keep from slipping while you turn it. You don't need as much grip strength, so your weak hands can do it.

The extra size added really doesn't make a difference.