# Ideal mechanical advantage. And ramps.

Ramps are cool.  By extending the distance outwards, we can push things up to the same height if we were to lift it, but it is easier. By extending the distance, the work still remains the same, but since the distance is longer now, that means we put in less force. And now for mechanical advantage. Mechanical advantage (or MA for short) is how much more easier it is to do something compared to doing it without the machine. So if you had to push a block up a ramp, and the ramp had a mechanical advantage of 2, then the block would be 2x easier to push up the ramp, then just lifting the block to the same height as the ramp. For more on this, I will leave a link at the bottom which will take you to another page talking about mechanical advantage.

Anyway,let’s do a practice problem! So we have a box full of stuff. And it is heavy. So we make a inclined plane for it. We want to lift this box 5 feet in the air, but now we have a ramp that is 30 ft long. So if we calculate the MA, which is the length over the height, we get MA=6. So our mechanical advantage is equal to 6 right?  Well, no. It gets more confusing. The MA isn’t 6, the IMA is 6. It turns out, that there is two types of mechanical advantages. Ideal mechanical advantage (IMA) and actual mechanical advantage (AMA). Today, I will be talking about IMA and maybe in a later blog post I’ll talk about AMA .

Ok, so what does Ideal actually mean? Well the dictionary definition of ideal is – something that we want to happen, but won’t actually happen in reality. So in short it means to imagine a perfect world with no blemishes.

So, in our last practice problem we got 6 for IMA, but why is it IMA? Well, in the problem we are imagining a world where there is no air resistance and friction. In this ideal world, the only factor here is the box and the ramp. However, in the real world, there is something called friction. This will slow down the box, meaning that the AMA isn’t 6 but actually the AMA <6. So basically, the IMA what the MA would be in a world that doesn’t have any other factors except for the machine and the load.

How to calculate IMA.

IMA is basically the length of the ramp/ the height for a ramp/incline plane. IMA = L / H for a ramp. However, IMA doesn’t only apply to ramps. Levers also have IMA formulas, and so do all other simple machines. For levers it is the effort arm length over the resistance/load  arm length.

link to my mechanical advantage stuff ^

Link to my what is mechanical advantage post ^

# What exactly is Mechanical Advantage??

http://blogs.scarsdaleschools.org/plin26/2020/05/25/ma/

Link to my other blog post about MA that I don’t recommend you read.

# MA<1 ?

Recently, I made a catapult which uses a lever and we had to find the mechanical advantage of the lever. However, while I was looking through some other people’s catapults, I was constantly seeing MA which was less than one. From what I know, MA is the ratio of how much force the machine will output from the input force. So a MA of 4 would mean the machine would output a force 4x the input. If so, then what is the point of a MA less than one? Would it still be an advantage? If a mechanical advantage is less than one, that means that the input force would be higher than the output, so wouldn’t it be easier just to do it without the machine? So I did some research over the weekend. First let’s start off with levers. If the effort arm is closer to the fulcrum then the load, the mechanical advantage will be lower. This means that all 3rd class levers will have a MA <1 , 1st class levers could also have a MA <1. However, second class levers will not do this.

So then, what exactly is the point of a 3rd class lever? First let’s look a a 3rd class lever.

This baseball bat is a third class lever. As it turns out, the point of this third class lever baseball bat is not power, but speed or velocity. We exchange MA for speed, the baseball bat is one piece, meaning the side that you are holding when you swing, that side will move quicker than the other, so in order for the other side to move at the same speed and time, the velocity of that side must increase causing the bat to go at a faster speed. Which means when the bat hits the baseball, the baseball goes faster. So the point of the 3rd class lever is to make things go faster, or increase their velocity, right? Well, not exactly. That is the main reason for a 3rd class lever, but there are others too. For example, take a some tongs. Tongs are a third class lever. But the point of tongs isn’t to make something go faster, the point is to pick something up. Usually we use tongs for ice. What is the problem with ice? Ice is slippery and hard to pick up ( also no one wants your dirty hands touching the ice that will go in their drink) so we use tongs. MA doesn’t really matter here, because ice is so light, that we will only be losing such a small force, that it isn’t really noticeable. Tongs are also used to pick hot food up, because we don’t want to burn ourselves. Again, food is usually so light that the force lost isn’t noticeable. We don’t care about the small amount of energy being lost, we care about getting food. So 3rd class levers have all kinds of usages, and just because they have a mechanical advantage of less than 1 doesn’t mean they are completely useless.

# FabMakerStudio

Last week in technology, we used this design website, called FabMakerStudio. It lets students design 3D or 2D things out of paper, so it’s kinda like CAD but not really? Anyway, I made a barn [see image below] from the list of pre-made 3D paper designs. This project involved a lot of cutting and glueing, which took some time but not a lot. The barn was originally supposed to have moving doors and windows, but that was too hard to be cut with scissor so I just cut out the door and glued it onto the barn. I made a paper barn using FabMakerStudio, and I really like it.

# Truss

I forgot to do a blog post last week, so I will do two this week. The next one will come out tomorrow. So in technology I made a cube out of toothpicks and marshmallows. Then I put books on it. Collapsed after only three. Then I realized that I forgot to film it for flipgrid, so I had to do build it again.  I also built a  cube with trusses. The cube without supports could only support a little weight before it collapsed, while on the other hand the one with trusses held up much more weight before the it finally broke.