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Simple machines: The inclined plane, the lever and the wedge
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What kind of simple machine is this?
Alright, Kim! To the top! But... Wait. What?
That's a wall! How am I supposed to walk up there? Look closer at the slope, Kim. Can you see the zigzag trail? Oh, yeah!
Of course. I can totally do this! Brilliant simple machine, this inclined plane, isn't it? - Whattya mean? What machine? - The trail. It is in fact a simple machine.
Simple machines are arrangements that help people carry out heavy work. Work? Well, in this case climbing a steep mountain hill. It would be impossible to walk up the hill without this inclined plane. The same arrangement was used in Ancient Egypt, - when... - Oh yeah!
I know! The construction of the pyramids. They built ramps and pulled the giant stones up the slope. Exactly. And the ramps are also examples of inclined planes.
I see. Never thought of them as machines, though. Simple machines. Pheew -- it's hot here. I'm gonna have some water.
There are other simple machines, you know. Yes? What others are there? Remember when you visited Seamus in the cabin? - When you chopped the wood. - Uhu. The axe is an example of a wedge. - A wedge? - Yes, a wedge -- Now, look at the axe as it's rammed by the sledgehammer. - I'm looking. - See?
The force of the sledgehammer is directed vertically, but the shape of the wedge redirects it in those two directions. This way, the wedge can be used - to split the wood. - Cool. Does this mean the knife is also a simple machine? Now you're catching on, Kim. The knife and the nail are two examples of wedges.
Good. There are simple machines everywhere, you know. Hmm -- Let me guess. The spit is a simple machine too? Indeed it is.
It's a kind of lever. - A lever? - Yes. Watch Seamus. See? He grips the spit above his head and pulls it all the way to the ground. The other end of the spit moves upwards.
Yes, but not as far. No, that's right. Seamus' end of the spit moves twice as far as the other end. Instead that end moves with twice as much force. That is called the Golden rule of mechanics.
What you gain in force - you lose in displacement. - Okay, I get it! And if Seamus uses a longer spit he can get even more force out of the lever? Yes. Now the distance is three times as long at Seamus' end, and the force three times as big by the block. The golden rule of mechanics.
What you win in force, - you lose in displacement. - Smart. Alright, I'm going to get going. It's a long walk today. It didn't seem that long on the map. No, but this is your actual route today.
It's less demanding but in return you have to walk a much longer distance. You know what we say... What you gain in force you lose in displacement. Very good. And this rule applies to almost all simple machines.
The inclined plane, -- the lever -- and the wedge. Whatever you gain in force you lose in displacement. I made it! What a view! Finally -- You don't even look tired. - Aren't you? - No. - You're a machine, Kim. - But not so simple, thank you!