The Top Ten

The Top Ten Places I See Physics

1.) In my room

I experience a Physics moment every time I sit in my desk chair and spin. 

As we learned when you sit in a spinning chair and are pushed you will go faster when you tuck your arms and legs inward. This is because of angular momentum. Angular momentum is your velocity times inertia. Inertia and velocity both depend on the distribution of mass. If the mass is closer to the center of rotation then there will be less inertia which means there would be more more velocity. There would also be less resistance since the arms and legs are closer to the body which means the angular momentum is faster. 

The angular momentum before = angular momentum after

She goes slower while your arms are out because they are further from the axis of rotation which means more resistance and more inertia which means less velocity. 

This is also seen in ice skating. 

2.) In my car. 

When I drive in my car and slam on my breaks I fly forward because of Newton's first law: an object at rest tens to stay at rest unless acted upon by an outside force.

You fly forward when you slam your breaks in the car because you are still moving while your car is stopping since and object in motion tends to stay in motion unless acted upon by an outside force. The seat belt is there in order to stop you from moving. Then when the light turns green and the car starts moving you are pushed back since you were at rest and the car is moving again. There is no force that is acting on you, it is just Newton's First Law. 

3.) In the Library.

When you place a book on the table, the book pushes the table and the table pushed the book right back with an equal force.

This is because of Newton's Third Law which states for every action there is an equal and opposite reaction. So when you place a book on the table in the library the book is actually pushing on the table and the table is pushing right back on the book with the same exact force. You would show this using vectors and saying table pushes earth earth pushes table then table pushes book and book pushes table. 

4.) On the field hockey field.

You learn when playing sports that you must always keep your knees bent, but why is this? 

The reason we bend our knees when playing sports is so that we move our center of gravity closer to your knees and to keep it inside your base of support which is your feet. By spreading your feet out you also widen your base of feet making it harder for you to fall over while playing a sport.

5.) In a garage.

In order to get a heavy object into a car you would generally use a ramp.

The reason you use a machine is because it lowers the amount of force needed by increasing the distance. As the distance increases the force decreases because work in=work out. The ramp is used to make it easier to push a heavy object into a truck because you don't have to apply as much force. If you were to lift the box, the distance would be a lot smaller but that means you would need to apply more force since both ways require the same amount of work. 

6.) On a roller coaster.

The reason we can make it through a roller coaster without stopping is because of the way the hills are designed.

You start off with a really high hill and then it goes to a small hill and then a medium hill. As the passengers KE increases due to the fact the hills go down they will go faster.  The energy you get while going up the roller coaster hill is called potential energy and it turns into kinetic energy as you go down the hill. Since an object in motion tends to stay in motion the roller coaster will continue to move forward in this way until an outside force causes it to stop.

7.) On my roof.

On most buildings there is a lightning rod to protect the home from being hit by lightning.

The lightning rod protects the home by providing an additional path for the lightning to take. It provides a path of least resistance so the lightning will choose this path to reach the path rather than the house or a tree nearby. The ground is positive and the ground is negative so that id why the lightning is attracted to the ground.

8.) Camping.

You want to make sure you having charged batteries before bringing your flashlight on a camping trip or else the light won't work.

In order to make a flashlight work in the first place there must be a complete circuit. The battery must be in contact with the lightbulb. The reason the light becomes dimmer when the battery loses its charge is because there is more resistance which means the light will become weaker. Also if the battery is fully charged and has voltage then the current will be stronger so the light will work but if the voltage is weaker than the current will be weaker.

9.) In the grocery store.

Whenever you are paying with a credit card the machine is able to read your card because of magnetism.

The credit card itself has a magnetic code and the reader has magnetic coils which induce voltage when the card runs through it ]. The reader will copy the card's code and the code will be transferred to the computer where it will then be authorized. 

10.) A toy car.

The motor in a toy car is operated by magnetism.

In general there is a battery with a magnet on top of it, two wires connecting to either sides of batter and connected to the metal loop above the magnet. The magnet will magnetize with the loop above it because the domains will align causing the loop to spin. The force must be perpendicular for this to happen and when it does the loop will move in one direction. The only way to change the direction is by changing the magnetic field.