# How does a screw roll down an inclined plane?

• I
• Tanreom
In summary, the conversation discusses the motion of a screw or cone on an inclined plane, taking into account factors such as friction, gravity, and normal force. The question is raised about how the screw would move, and the suggestion is made to conduct experiments. The idea of the screw pendulating back and forth as it rolls down the plane is also mentioned. The possibility of using an ice cream cone for the experiment is suggested, and a link to a mathematical analysis of the motion is provided. The conversation ends with a question about the screw rolling only on its head and tip.
Tanreom
TL;DR Summary
How would the motion of a screw rolling down an inclined plane work?
I was thinking about how various objects would slide down on an inclined plane, and I just couldn't figure this problem out.

So let's say I have this screw or cone on its side, on an inclined plane. If friction exists, what would the motion of the screw be as it slides down the inclined plane?

There is no initial velocity and no air resistance either. The only forces acting on the object would be gravity, normal force, and friction.

I know that the screw is apparently supposed to pendulate back and forth as it rolls down, kinda like a zigzag curve, but I'm not sure how that would be...

Edit: I have tried experiments, and the screw seems to oscillate as it rolls down the incline. What I don't know is how to quantitatively anaylze the motion using mechanics.

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I imagine the base of the cone would begin to roll downward about its apex. The apex wouldn't move. The effect would be like a pendulum rolling on a plane about its apex.

Or the base of the cone would begin to roll downward about its apex. The apex in turn would be pulled down too, and the base of the cone would track a kind of zigzag curve as it rolled back and forth sliding down the plane.

And some math to go along with it:

https://www.mathpages.com/home/kmath227/kmath227.htm

Lnewqban
Have you thought about doing an experiment? An ice cream cone might work, without the ice cream of course.

Tanreom said:
Summary: How would the motion of a screw rolling down an inclined plane work?

I was thinking about how various objects would slide down on an inclined plane, and I just couldn't figure this problem out.

So let's say I have this screw or cone on its side, on an inclined plane. If friction exists, what would the motion of the screw be as it slides down the inclined plane?

There is no initial velocity and no air resistance either. The only forces acting on the object would be gravity, normal force, and friction.

I know that the screw is apparently supposed to pendulate back and forth as it rolls down, kinda like a zigzag curve, but I'm not sure how that would be...
Screws and inclined planes are INCREDIBLY easy to come by. Do an experiment.

I have done experiments, in fact. But I don't know how to quantitatively analyze the motion...

Welcome!
I assume the screw is rolling only on its head and tip.
If in static condition, with the tip pointing up, the screw does not slide down the plane, but it does when rolling and swinging, then the centrifugal efect when the tangential velocity of the head is around maximum value, as well as kinetic friction, should be what makes the difference.

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## 1. How does gravity affect a screw rolling down an inclined plane?

Gravity is the force that pulls objects towards the center of the Earth. When a screw is placed on an inclined plane, gravity acts on the screw and pulls it downward. This force causes the screw to roll down the inclined plane.

## 2. What is the role of friction in a screw rolling down an inclined plane?

Friction is the force that opposes motion between two surfaces in contact. In the case of a screw rolling down an inclined plane, friction between the screw and the plane helps to slow down the screw's motion and prevent it from sliding down too quickly.

## 3. How does the angle of the inclined plane affect the speed of the screw rolling down?

The steeper the angle of the inclined plane, the faster the screw will roll down. This is because the steeper angle increases the force of gravity acting on the screw, causing it to accelerate more quickly.

## 4. Why does a screw roll down an inclined plane instead of sliding?

A screw has a circular shape with threads that provide grip and prevent it from sliding down the inclined plane. As the screw rolls, the threads dig into the surface of the plane, creating friction and allowing the screw to roll down in a controlled manner.

## 5. How does the mass of the screw affect its motion down an inclined plane?

The mass of the screw does not significantly affect its motion down an inclined plane. The force of gravity acting on the screw is proportional to its mass, so a heavier screw will have a slightly stronger force pulling it down the plane. However, the shape and angle of the inclined plane will have a greater impact on the screw's motion.

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