Aerodynamics

Aerodynamics is a branch in physics studying the motion of an object and its interaction with air.  The picture to the left shows the vortex created by an airplane due to the difference in pressure. A red smoke is usually used as an indicator to study the motion of air. The 2 sub-topics in aerodynamics fluid dynamics and gas dynamics.

The glider depends heavily on the density of its medium. In air for example, the glider will glider further in a higher air density environment, because the more air particles the wings catch, the further it will glide.  The aircraft's resistance to the airflow (drag) depends on the shape of the fuselage and flying surfaces. An aircraft that is intended to fly fast has a thinner and different wing profile than one that is intended to fly slower. That's why many aircraft change their wings' profiles on landing approach by lowering the flaps located at the wings' trailing edge and the slats at the leading edge in order to keep enough lifting force during the much lower landing speed.

5 projectile motions, questions, and answers

Homework

Drawing the graphs

Graph #1  d/t

v/t

Graph #2 D/t

v/t

Graph #3v/t d/t

Graph #4v/t

d/t

a/t

Graph #5d/t

v/t

Walking the graphs

Again, this probably was the most effective way to start a new chapter :)
This lab helped me understand the real motion behind the science of motion.
Probably the most fundamental knowledge that is important to later studies.

I definitely learned a lot from this activity, from how a motion sensor works, to how to plot a graph with the change in speed and distance.
I personally think these activities help me understand the physics behind the math, and its a awesome way to understand the concept before applying them.

Looking forward to more labs!!!!!!!!!!!

Right Hand Rules.

Based on Oersted's principals of current and magnetic field, three right hand rules can be applied to help us understand some concepts. Firstly, we must understand that all right-hand rules are based on the concept of conventional current, which is the movement of protons from positive to negative. If electron flow is considered, the same results can be obtained by using the left-hand rule.

Right-hand Rule #1



 Right-hand rule number one states the relationship between the direction of current flow and the direction of the magnetic field generated as a result. Given either one of the variables, the other can be determined.
Taking the above diagram as example, the direction of the thumb pointing at represents the direction of the current. The direction of the fingers holding the conductor therefore represents the direction of the magnetic field.

Right-hand Rule #2
 
 

The right-hand rule explains the concept when a conductor is coiled around a metal, magnetizing the metal.  In this case, the fingers will point to the direction of current flow, and the thumb will reveal the north of the magnet.

Concept Map + must knows for electricity

 

This is the concept map  we created to summarize this entire unit :) Below lists some of the most important terms you must know for this unit.

Series Circuit - a complete circuit with all the loads/resistors connected in a                                                   continuous connection, if one load/point is removed or damaged, the entire circuit fails.

Electron Flow - the flow of electrons (-) in a circuit from the negative terminal to the positive terminal.

Conventional Current - the flow of protons (+) from the positive terminal to the negative terminal.

Coulombs (Q) - the measurement of the number of electrons, in the unit of C

Current (I)- the measurement of electron flow using an ammeter in the unit of A (Amperes)

in the formula I= Q/t

Voltage(V) - a measurement of electric potential energy between two points in the unit of V (Volts). This        is calculated by the formula V= E/Q, where E is the energy required to increase the electric potential of a charge, Q.

Resistance (R) - is the measurement of the opposition to flow, measure in the unit , this is calculated by the formula R = V/I.

Ohm's Law - this law presents a significant relationship between resistance, voltage, and current. Voltage and current displays a linear relationship to each other, and the slope remains constant in the same graph. The slope is the resistance of a circuit, which do not change under variations of voltage/current.

Kirchhoff's current law - The total amount of current into a junction point of a circuit equals the total current that flows out of that same junction.

Kirchhoff's voltage law -  The total of all electrical potential decreases in any complete circuit loop is equal to any potential increases in that circuit loop.

Power - the rate which work is being down, can be calculated by the equation P = IV

Ohms vs. Kirchhoff

Ohm's Law

Ohm's Law states that the current flowing through an conductor between two points is proportional to the potential difference (V) between the two points.The relationship between the two will show an linear relationship (seen above). Where the increase of Current results in the increase in Voltage. Ohm's also states that resistance, will stay constant regardless of the change in current or voltage.

Resistance - opposition to the flow of electrons.

The formula purposed to represent this relationship is R= V/I

Kirchhoff's laws

Kirchhoff, a brilliant German physicist takes on Ohm's law and expands it into another concept within the circuit. The six laws he purposed presents the relationship in Current/Voltage/Resistance between all the loads in a single circuit.

 Parallel Circuits  

The first law states that the total current (number of electrons) of a circuit equals to the sum of the current of all the loads.                                                        

1. It = I1 + I2 + I3 + .. In

The second law states that the voltage (potential difference) of all the loads within a circuit will equal to each other. 

2. Vt = V1 = V2 = V3

The third law represents the relationship in resistance (opposition to electron flow) between the loads within a circuit.

3. 1/Rt = 1/R1 + 1/R2 + 1/Rn

Series Circuits

The first law in the series circuit states that the current measured in each load within a circuit will equal to each other.

1. It = I1= I2= I3= In

The second law states that the total voltage in a series circuit is the sum of the voltage of all the loads.

2. Vt = V1 + V2 + V3 + Vn

The third and final law states that the total resistance of a series circuit equals to the sum of all loads' resistance. 

3. Rt = R1 + R2 + R3 + Rn 

Favourite Rollercoaster :P

Despite of the magnificent amount of physics and mathematics behind a roller coaster, its still a ton of fun riding on one :).
So.. down to the point, my favorite  roller coaster "SO FAR" is the Behemoth (hey, I know I haven't been to any amusement park outside of Canada yet, but that's not the point), it's still the fastest and highest coaster in Canada right? And, just for the fact that I am a proud Canadian. At you go down the first and the highest hill, its such an amazing experience, and the fact that you can't visually see the tracks on the top just makes it more thrilling. For those of you who are in fear of roller coasters, don't be scared, because your fear is the most fun part after you step out of the coaster. And since we are physicist, you can always take out your calculator and see you wont fall out of it. right? :)

Battery --> Load ---> Battery

A circuit as we know today, is a pathway for electron flow from the source and back to the source.
The source that is most often used today is a dry cell, or battery.Chemical reaction inside the battery produce charges that will later be used as heat/light energy in a load.

Current (I) measured in Amperes represent the number of electrons passing through a certain point in the circuit for a given unit of time.

I = Q/t      Where Q is the symbol for charge measured in Coulombs.

It is important to understand the conventional current as thought by Benjamin Franklin, is the measurement of protons in a circuit. However, as we became more knowledgeably we discovered that it was actually the electrons(-) that are passing through, we call this electron flow.

As electrons passes through a source, it gains potential energy, which will later be transformed into heat/light energy. This energy can be also called electric potential difference which we commonly refer to as Voltage (V) measured in Volts.

V = E/Q  where E is the symbol for energy (work) measured in Joules.

The voltage can be measured with a ammeter shown below.

Energy Ball Circut

                                          

Series Circuit

The very first scientific activity we did in class today was about electrical circuits, where we investigated the differences between series circuits and parallel circuits.

Parallel Circuit

Each group of approximately 4 people were given a energy ball that would flash and sound if a correct circuit was established. For learning purposes, each group was given a dozen questions to answer, such as including 2 energy balls in the circuit. It was surprising that our bodies could act as wires and the energy ball was able to function in a closed circuit.

I think this activity was definitely a fun and awesome learning experience, while the questions kept us thinking and learning.
The idea of working in groups was also very enjoyable, because i felt much more relaxed working in a group and the fact that we could exchange ideas was also very helpful.
            
An experiment during our first class did take me by surprise, and I think I am starting to love this class. Definitely looking forward to future classes and more awesome activities!

p.s. the class challenge at the end was very very cool :)