Bernoulli's principle

The fancy way:




For dummies: as the velocity of a fluid increases, the pressure exerted by that fluid decreases.


Even simpler: Velocity increases = pressure decreases



Its what make airplanes fly.

The air on the bottom maintains the same path and stays the same speed. The higher pressure on the bottom pushes the wing, and the plane, up.

Time to study water rockets

So go to aircommandrockets.com and do it. Ok? Good. Cause you can tottaly build this.

Charles Law and other Pressure Stuff

Kinetic Energy

Everything is made up of molecules. These molecules are never still. They are always wiggling around being pulled by different forces.



Look! Now you’re doing chemistry

Bonding

The molecules are all held together by bonds. These bonds are like holding hands with another person. You can hold on tight or you can hold on loosely. You can pull together or you can be stretched apart. You can be pulled apart with force or you can twirl around each other.



As the temperature increases, the molecules move faster. The faster they move, the more bonds they break. The molecules then spread out, bouncing all over everywhere. They are now a gas.

When the molecules are at room temperature they are wiggling a little with kinetic energy. In this state they are loosely bonded to the other molecules. They can hold on, there aren’t many forces pulling. This is why liquids flow.



Charles Law

When heat is added, the molecules begin to move faster and faster. This causes them to need more space and pressure to increase.



As temperature increases, pressure increases.

Why Should You Care?

If the molecules have room to defuse (spread out) all is good.

Inclined Planes

What it do

A simple machine consisting of
a flat surface which creates a slope from a horizontal plane and is used to reduce the force necessary to overcome gravity when elevating a heavy object

A ramp is an example of an inclined plane. By using a ramp less effort is needed than if you were to try and lift the object



A standard inclined plane does not move. It is merely a ramp. Objects move easier either up or down, but the plane is stationary. Examples include things such as bike jumps, trail switchbacks, and boat launches.

A screw is also an inclined plane twisted around a rod or shaft as to apply the force into another object.

A wedge, like an axe, or a sword, is a double inclined plane designed to be driven into another object using directional force.

And now onto the fun part....

Pythagorian Therum

a2+b2=c2 - write this down.

a is the opposite side and how high you are trying to lift the object.

b2 is the adjacent side and the horizontal distance the inclined plane covers.

c2 is the hypotenuse and the slope of the inclined plane. This is the distance the object actually travels across

Mechanical Advantage

Mechanical Advantage is the amount the machine multiplies the force put into it. This is the amount of advantage you receive from using the machine.

Force applied = Mechanical Advantage x Force Needed

MA= resistance height /effort length

Instead of lifting the heavy object straight up in the air, you space out the same force over a long distance. This way you are slowly fighting a small amount of gravity rather than trying to overcome the entire gravitational force all at once.

Bringing it all together

You decided to skip Mr. Evans’ physics class to play World of Warcraft……again. Sure it was fun, but there was one problem. He found out.

He called your parents and they dragged you back to school for detention.

Mr. Evans felt such a horrific crime needed manual labor to help build character. He said you had to load heavy crates full of bicycle magazines into the back of his pickup truck and you could only go home when the job was done.
What are you going to do?!?

So riddle me this-

How long is the board going to have to be for you to effectively use it?

How much force are you going to have to push with to move each crate?

How much nicer would it be to have gone to Mr. Evans’ class in the first place?

You begin reading notes from a previous class, determined to do something.

Some quick estimation and you decide each crate weighs 100 pounds.


Just then you notice a large, astonishingly indestructible, board from a local construction site. You place the board at the end of the truck’s tailgate creating…


Some quick phone calls and you decide none of your friends is willing to come help you.

Hint: The bed of the truck is 3 feet off the ground and the crates are 4 feet from the truck.
No, you can’t just lift them, you play too many video games and are out of shape. As always, there are multiple answers as long as you can explain them.