We See Physics Everyday

Ayana Tiller

Mr. Berkil

5/1/12

COULOMBS LAW & CHARGE INTERACTION My Mother and I have often not seen things eye to eye and for the most part, a teenager girl and her mother may be seen as opposites.

According to how charged particles behave, opposites attract. In this picture you can see that there is a Force drawing us together just as if we were oppositely charged particles.

The force of two charges can be calculated using Coulomb’s equation: F=KQ1Q2/r2. F=force, k=constant, Q1&Q2 are two charges and this is divided by the radius or distance squared.

Since my Mother and I can be looked at as oppositely charged particles, we also create an electric field. The closer the charges are to each other, the greater the attractive Force within the electric field. We have created an electric field of LOVE!

FIRE & COMBUSTION Fire is a gas that is hot enough to incandesce, or cause to glow with heat. The colors that you see in the flame are due to temperature.

Some of the electron structures of elements and compounds absorb this energy and excite the electrons. These electrons emit photons of a particular color.

When something is heated enough, it reacts with oxygen in the air. This reaction called a Combustion reaction.

This reaction is an exothermic reaction. This means that the reaction gives of heat.

VELOCITY

• Velocity is speed in a given direction. It is a vector quantity that differs from speed, a scalar quantity, in that it is defined as displacement/time.

• The units of velocity are m/s in a given direction.

• The velocity of a moving object is either constant or changing. When it is changing , this is called acceleration. This means that acceleration is also a vector quantity.

• In this picture, you can see me sitting in a moving car moving East on I-20 at 60mph.

• Almost Home!

SPEED The speedometer is a device that measures speed. Speed is a scalar quantity (it only has a number and units.)

Speed measures how fast or slow something is going and it can be calculated using this equation:

Speed = distance traveled/time.

units = meters/second or miles/hour.

Speed is a scalar quantity (only units and a number)

When we look at the speedometer to see how fast we are driving, it tells us not only the speed but at that very second, is also tells us the instantaneous velocity (or speed at that VERY second) which is a vector quantity because velocity has a direction, a number and a direction.

AIR RESISTANCE

We can all probably guess that if you drop a bowling ball and a piece of paper from your roof, the ball would hit the ground first. But why is this the case if gravity has the same acceleration on all objects (9.8m/s2)? Air resistance is a force that slows down moving objects. Two things affect how an object is affected by air resistance. They are MASS AND SHAPE. If an object is very massive (the bowling ball) it can overcome the force of air resistance. If the shape of the object is spread out ( the paper), it is more affected by air resistance and slows down.

Lets do a simple experiment: Everyone take out two sheets of paper.

If you crumble on of them (its not spread out), and leave the other one flat, WHICH WILL HIT THE GROUND FIRST?

The crumbled one will hit the ground first because it has less surface area (its not spread out) so less air resistance!

GRAVITY

Gravity is a natural force that pulls matter towards the center of the earth. It is an attractive force that causes objects to accelerate at the rate of 9.8m/s2. The force of gravity INCREASES with two different factors: Increasing the mass of an object or decreasing the distance the object is from earth.

F=GM1M2/r2 is the equation that describes how the force of gravity affects objects. In this picture, you see a ball at the edge of the table and the force of gravity is the force that makes the ball drop.

NEWTON’S 3RD LAW

Newton’s third law is not always so easy to see but it states that anytime a force is put on an object, that object also exerts an equal amount of force on the first object but in the opposite direction. So, if you push on a wall, the wall is also pushing back on you with the same force in the opposite direction.

BUOYANCY

Buoyancy is a force that is exerted by a fluid, ex water, that directly opposes The weight of the object. Weight is calculated by using this equation:

w=mg

(m is mass and g is gravity).

Since the buoyant force keeps things floating and pushes upward on all objects in a fluid due to the fluid pressure , it depends on two things: Density and Pressure

In this picture, we can see a ball floating in this sink filled with water. The ball is floating because the buoyant force is able to overcome the effects of the weight of the ball.

SIMPLE MACHINES-WHEEL AND AXLE

Machines are tools that make work easier. They do this by changing the strength or direction of a force. They can also change the distance an object needs to move

I’m in the grocery store and I am pushing a shopping cart because it makes it easier for me to move all of the items I want to purchase. The way it works is pretty simple: The wheel causes the axle to turn and do work.

MIRRORS-LAW OF REFLECTION

When a light ray hits a flat mirror, it is reflected at the same angle it hits. The light waves we see are a reflection.

As I looked in the mirror to take a picture of myself with my cell phone, the mirror reflected the light and it follows the law of reflection.

This law states that the angle of incidence equals the angle of reflection for the light that hits the mirror.

The image in a plane mirror looks exactly like the real thing. That's why, if you look in a mirror, you see your face exactly the way it is.

SIMPLE MACHINES-INCLINED PLANE

A machine cannot decrease or increase the amount of work done, but it can greatly reduce how much force is needed to get the job done.

In this picture you see an incline plane or a ramp, as we usually call them.

Inclined planes decrease the amount of input force needed, although the amount of work remains the same.

Input force is the amount of force you put on the machine. Output force is the force the machine puts on the object.

ALTERNATIVE ENERGY-SOLAR POWER When you look at how expensive gas prices are, you wonder when we will include alternate sources of energy and utilize them as much as we use fossil fuels.

My generation doesn’t really seem to care as much as we should but the Earth can not deal with “abuse” for so much longer.

Solar energy is the harnessing of radiant light and heat from the sun.

This is a renewable resource that will not run out, but reduce particulate matter from the air , CO2 emission and global warming as well as keep gas prices low.

Solar technology can either be active or passive depending on the way we capture, convert and distribute sunlight.

The only drawback is that it is not equally available to everyone, especially if you live in a place with limited sunlight.

PROJECTILE MOTION

When an object is in free-fall, this means that gravity is the ONLY force acting on that object.

In this picture, you see a football being thrown. This football is in projectile motion because gravity will bring this football down to the ground in the vertical direction at an acceleration of 9.8 m/s2.

Projectiles have two independent components: horizontal and vertical.

The horizontal component is due to the velocity ex, how fast we are throwing the football while the vertical components is due to gravity causing a curved path.

FOSSIL FUELS & ALTERNATIVE ENERGY What are fossil fuels and why are they so important?

-Fossil fuels are non- renewable resources (they take millions of years to form and are being depleted much faster than its being made).

-They are fuels that come from the breakdown of buried organisms from millions of years ago.

Our dependence on fossil fuels such as coal and natural gasoline has had a major impact on our pockets and even the Earth as we know it.

We depend on it to fuel our cars and our economy depends on it to do everything from electricity to fueling semi trucks to deliver all of the goods we enjoy like our clothing and electronics.

SO WHAT IS THE PROBLEM?

Global Warming!

Carbon Dioxide (CO2) is released when we burn fossil fuels and this is warming the Earth and ruining the ozone layer. As a result, there is a world-wide movement to look into alternative energy sources like solar power and wind which are renewable resources (they are sustainable and will not run out).

MOMENTUM AND COLLISONS

When you measure motion using mass and velocity, it is momentum you are measuring. Momentum can be calculated using the equation, P=MV. The units for Momentum are kg*m/s. Momentum and Velocity are both vectors and so is momentum. In this picture, you see a collision between two balls. There are two types of collisions: Elastic and Inelastic.

If the objects bounce off each other it is elastic. This is the type of collision between the two balls. If the objects stick together and move as one big object, it is inelastic. All collisions obey the law of conservation of momentum. This states that the total momentum between two objects before the collision is the same as the total momentum after the collision

EMECTROMAGNETIC RADIATION MICROWAVES

Anytime you listen to the radio, heat up your food in the microwave or if you have ever had an X-Ray, you are seeing electromagnetic waves at work.

These waves are different from mechanical waves because they do not require a medium. These waves result from alternating electrical and magnetic fields. The major source of these waves is the sun.

Technology has allowed us to produce these waves and this is how I was able to heat my food using a microwave.

Can anyone guess how a microwave works?

The electromagnetic microwaves deliver energy into the food. This causes molecules in the food to vibrate, which makes heat.

YUMMY!

NEWTON’S 1ST LAW Have you ever wondered why it is so important to wear your seat belt? Well the answer can be found when we look at Newton’s 1st law:

This law states that an object will continue to do what it is doing unless an outside force acts on it. So, if an object is at rest it will remain at rest and if an objects is in motion, it will remain in motion.

Inertia is the tendency of an object to resist changes in motion.

If you are riding in a car and the person driving slams on the breaks, what happens to the passengers? They will continue to move forward. The seat belt stops you from flying out the window!

WEAR YOUR SEATBELTS AT ALL TIMES!

FRICTION

• Friction is the force between two objects as they move past one another. There are two types of friction: Static (if the object is not moving) and Kinetic (if the object is moving).

• In this picture, you see an image of a treaded tire. It is important to have friction between your tires and the road because it determines how fast you can accelerate as well as how fast you can stop if you need to.

• Treads channel water so you can’t hydroplane in the rain. If anyone has EVER experienced this in a car, you know how scary this is. Thank GOD for physics!

• Every sound you hear is a wave of energy called a sound waves. These waves are mechanical waves which means that they can only move through a medium (ex., air, water, solids). Sound waves are longitudinal waves which is a type of mechanical wave. Longitudinal waves travel parallel in the medium. To make sound waves, this is what happens:

• 1. Something causes an object to vibrate, like the electricity in the stereo. 2. The vibrating object now has energy which is transferred to the surrounding air particles. 3. Vibrating air particles bump into other air particles, causing them to vibrate. 4. All the vibrations going back and forth lead to waves, which carry sound energy from the source to the surrounding area

• You see the picture of a speaker and this is what has to happen to amplify sound waves:

• Speakers increase the Amplitude which shows how much energy a wave is carrying. With sound, we hear a difference in amplitude as a difference in volume.

• So when you crank that Usher or Beyonce, the louder sound results from a large amplitude and increase energy of the sound wave.

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SOUND WAVES

ENGINES & ENERGY CONVERSION

It is so easy to get into a car, turn the key, and start moving. Its hard to think about physics when you just want to get to where you need to be.

Well, physics is always in motion and the purpose of a engine is to convert gas (energy) into motion by burning the gas inside. This creates an internal combustion engine.

When you are ready to move, an electrical engine converts electrical energy into mechanical energy.

You can contrast this to a generator which converts mechanical energy to electrical energy.

LIGHT

• In the dark nothing can be seen, we need light for things to become visible. The way this works is that objects reflect light and this light hits your eyes. The reason we see things is because light reflects off the object and back to you. Light travels in waves

ELECTRICITY

• If you have an I-pod, cell phone or a computer you will definitely need electricity to charge these items. You know that we cannot live without them!

• Electricity is simply the flow of electrons.

• If you have ever rubbed your feet along the carpet and touched someone, you may have felt a shock.

• This is static electricity which is an accumulation of excess charge because some objects have more electrons than normal.

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CONSERVATION OF MECHANICAL ENERGY

• Each type of energy is a different form of energy. This energy is never created nor destroyed, it is just transferred from one form to another. This concept is the conservation of energy.

• Mechancal energy is the energy something has as a result of its position, Potential Energy (PE) or motion, Kinetic Energy (KE).

• Look at this picture of a roller-coaster at Six Flags.

• Potential energy is stored energy. This is the purpose of the first hill. This is usually the tallest hill to build up the most energy that will be used as it is converted to kinetic energy.

• The PE is greatest at the maximum height and decreases as it goes down towards the earth. KE increases as PE decreases.

• The formula to calculate PE = mgh (m is mass, g is gravity and h is height )

• The formula to calculate KE =1/2mv2 (m is mass , v is velocity squared).

NEWTON’S SECOND LAW

• This image depicts a car crash. For this to happen, a force must have acted on this object. This force to cause the damage came as a result of a massive car with an acceleration.

• Newton’s 2nd law can explain this: F=ma, (F is force, m is mass and a is acceleration , units are kg.m/s2 or Newton's) states that the Force acting on the car is a result of the mass x acceleration of the second car.

• In contrast, if the second object were a bike, the damage would not be so great because the mass and acceleration of the bike would not have had such a force and would not have damage the car so greatly.

AERODYNAMICS

• This airplane flying in the air is so fascinating to me. The study of how this works is called Aerodynamics which studies motion in air.

• The one thing that you have to realize is that the clear sky you see is not empty. The air is a fluid.

• An airplane takes advantage of four forces, LIFT opposes the weight (mg), THRUST is the forward motion and DRAG opposes the thrust.