Screw

[kidcoder923]

so then will it count as an incline plane?

[goodcheer]

I was planning a stationary screw that doesn't move itself, but that a marble would move through it. But after reading the rules, it sounds like the screw itself needs to move, not just the marble. I'm confused.

The screw must turn or rotate, but the screw itself does not have to move forward or backward. It can turn and move an object like a marble forward or backward depending on the rotation of the screw. The word "stationary" seems to need clarification. If you use a screw driver to turn a screw, in common usage, the screw moves forward into an object such as a piece of wood. In this usage of a screw, the wood is stationary. But, if the screw is stationary (that is you prevent it from moving forward or backward) and you turn the screw, a piece of wood can move along the threads of the screw as long as the wood is not stationary. There are many examples where this is used, such that when the screw is turned, it tightens an object but it stays in place, such as in a computer case.

[mderoller]

We would like to connect a wheel and axle to a screw in such a way that both are scorable. One idea is for a weight attached to a string that is wound around the wheel to fall, there bye rotating the axle. Can the rotating axle power the screw directly and still be scorable as a wheel and axle and a screw?

[mderoller]

Nevermind, after rereading the rules, specifically 3i I understand "each object that is a simple machine may only be counted as a simple machine once". In my example it can be a scored as a wheel and axle, or screw, but not both.

[goodcheer]

Nevermind, after rereading the rules, specifically 3i I understand "each object that is a simple machine may only be counted as a simple machine once". In my example it can be a scored as a wheel and axle, or screw, but not both.

It seems what you are describing is that the screw would simply be an extension of the axle, so you are probably correct. However, if you connected a second string from the axle to the screw, then you would have a wheel and axle transfer to a screw and both would count. The problem becomes, how to turn the screw. What if you did two of the same set ups in a row and called one of them the wheel and axle and the other one a screw? You can place a spool on the head of a screw, such that when the spool turns, the screw turns. Seems to be the same idea you have. Happy possible mission.

[mderoller]

Thanks for the response. We are using a string tied to a screw with a weight. When the weight drops the screw rotates many times on a nut that is fixed. What we would like to do is have the screw blocking a hole above it. When the screw rotates it moves to one side, unblocking the hole and letting something fall through. Would that count as a screw and a scorable transfer? Thanks.

[goodcheer]

Thanks for the response. We are using a string tied to a screw with a weight. When the weight drops the screw rotates many times on a nut that is fixed. What we would like to do is have the screw blocking a hole above it. When the screw rotates it moves to one side, unblocking the hole and letting something fall through. Would that count as a screw and a scorable transfer? Thanks.

Sounds like it would count, as long as the screw rotated at least two full turns.