There are many forms of energy in the world. Today, i will talk about some of these types of energy.
Chemical Potential Energy:
This energy involves atoms and molecules. Chemical bonds form within these molecules. In other words, objects that do work from fuels have chemical potential energy. For example, a car has chemical potential energy from the gas it has within it.
Mechanical Kinetic Energy:
Before I get into mechanical kinetic energy, we need to know what mechanical energy is first. Take a strongman lifting weights in the gym. As he is lifting them up, he is doing work. When an object does work, they are using mechanical energy. So what is mechanical kinetic energy? That's the energy the object with mechanical energy transfers to the other object, causing it to have a displacement. This object has now moved, and whenever an object is said to be moving, it has kinetic energy.
Gravitational Potential Energy:
This is the energy any object has because they are on Earth. Earth's gravity pulls down the object, causing it to have gravitational potential energy.
Elastic Potential Energy:
This energy involves elastic objects such as slingshots and bows. When a projectile is placed on the string of these objects, and the string is pulled back, the tension in the string builds up. When the string is let go, all that elastic potential energy is transferred onto the projectile, launching it forward.
Thermal Energy:
This is energy that deals with heat and temperature.
Sound Energy:
Energy that involves vibrations from an object.
Friday, December 10, 2010
CANNONS
We built cannons last week and today we finally fired them. Our materials that we had to bring were: 5 pop cans, 2 styrofoam cups, duct tape, and a can opener. The cannon is built with 3 cans and the base is built with 2. The goal is to get as much distance as possible on the x axes. In order to acheive that, we built our cannon at a 45 degree angle. Our cannon was able to get the furthest distance in the class, at 260 m. It also caught on fire from the hole XD. But Jonathan reconstructed it, Good job Johnny!
Tuesday, December 7, 2010
4 Newton Problems
For all of these four problems, break them down to a FBD with x and y axes and set your positive axes.
Equilibrium:
This is when the object isn't moving and all the forces are equal to each other. The object is usually hanged up by two strings or beams. Using trig will find the unknown angle or side, depending on which is given.
Inclines:
This is where you have a slanted surface and an object at the top of that surface. There is a friction force acting on the object as it slides down the slanted surface. the equation for friction is mu*fn. The FBD has to be shifted a bit in terms of x and y.
Pulleys:
There are 2 FBDs for these types of problems, one for each object on the 2 ends of the pulley. We assume there's no friction and tension is the same for both sides.
Trains:
These are similar to pulleys. You still need 2 or more FBDs, depending on how many cars you have on the train. When your trying to find the acceleration, draw a FBD of the whole system. Friction is included in this problem. To solve for tension, you have to find each individual tension between each 2 cars.
Equilibrium:
This is when the object isn't moving and all the forces are equal to each other. The object is usually hanged up by two strings or beams. Using trig will find the unknown angle or side, depending on which is given.
Inclines:
This is where you have a slanted surface and an object at the top of that surface. There is a friction force acting on the object as it slides down the slanted surface. the equation for friction is mu*fn. The FBD has to be shifted a bit in terms of x and y.
Pulleys:
There are 2 FBDs for these types of problems, one for each object on the 2 ends of the pulley. We assume there's no friction and tension is the same for both sides.
Trains:
These are similar to pulleys. You still need 2 or more FBDs, depending on how many cars you have on the train. When your trying to find the acceleration, draw a FBD of the whole system. Friction is included in this problem. To solve for tension, you have to find each individual tension between each 2 cars.
Projectile Motion
There are 4 types of projectile motion questions. For all 4 types, we use the big five to solve them.
Type 1:
x: y:
ax = 0 ay = gravity = 9.8m/s^2
vx is constant vy = 0
dx = (vx)(tx) dy = height
Time is equal for both x and y
Type 2:
x: y:
ax = 0 ay = gravity = 9.8m/s^2
vx = v1cos(θ) vy = v1sin(θ)
dx = Range dy = 0
Time is equal for both x and y
Type 3 & 4:
These two are similar to Type 2. The only difference is that Type 3 has a positive dy and Type 4 has a negative dy.
Type 1:
x: y:
ax = 0 ay = gravity = 9.8m/s^2
vx is constant vy = 0
dx = (vx)(tx) dy = height
Time is equal for both x and y
Type 2:
x: y:
ax = 0 ay = gravity = 9.8m/s^2
vx = v1cos(θ) vy = v1sin(θ)
dx = Range dy = 0
Time is equal for both x and y
Type 3 & 4:
These two are similar to Type 2. The only difference is that Type 3 has a positive dy and Type 4 has a negative dy.
Rollercoasters
We're building rollercoasters for our summative. Each group has about 4 people. It's gonna be very interesting to see what the final outcome of our rollercoaster to look like, I can't wait! Some of my favourite rollercoasters I've seen from past years are the mario speedway and the iron man coaster
Monday, October 25, 2010
How to Add Vectors
When presented with various vectors, and we're asked to add them up, how do we do it? Do we just add the length of the displacements together? If only it were that simple...
Here are the steps on how to add vectors.
1.) First, look at the equation given to you. If there are negatives (eg A - B), change it around so that it's adding the negative (eg A + (-B)). The negative only affects the direction of the vector, not the value. So if B was going East, negative B will be going West.
2.) If the vector is at a degree, change it so that it is represented by a horizontal x and a vertical y.
3.) Solve for x and y.
4.) Add up final x and final y with the Pythagorean therom.
5.) Use some simple trigonometry to solve for the angle.
Here are the steps on how to add vectors.
1.) First, look at the equation given to you. If there are negatives (eg A - B), change it around so that it's adding the negative (eg A + (-B)). The negative only affects the direction of the vector, not the value. So if B was going East, negative B will be going West.
2.) If the vector is at a degree, change it so that it is represented by a horizontal x and a vertical y.
3.) Solve for x and y.
4.) Add up final x and final y with the Pythagorean therom.
5.) Use some simple trigonometry to solve for the angle.
Wednesday, October 20, 2010
Deriving equation 3 and 4 from the v-t graph
The standard velocity-time graph.
Equation 3 is written as d = V1Δt + ½aΔt².
On a v-t graph, when we are looking for distance, we find the area of the trapezoid shape.
We can do that by dividing the trapezoid into a square and triangle.
The formula to find the area of the triangle is ½(V2-V1)t. Equation 1 states that at= V2-V1. Sub equation 1 into the formula. ½at²
The formula to find the area of the rectangle is V1*t, also known as V1Δt.
Combine these 2 formulas to create equation 3, d = V1Δt + ½aΔt².
Equation 4 is written as d = V2Δt - ½aΔt².
On the v-t graph, we can derive equation 4 by making the graph look like this big rectangle.
Then find the area of the triangle within the rectangle. ½(V2-V1)t. We know from equation 1 at = V2-V1.
½aΔt².
Combine the two formulas to create V2Δt - ½aΔt².
Tuesday, October 12, 2010
Motion in Graphs
Last week, we did a lab on distance/time graphs and velocity/time graphs. Here are the 6 graphs we made:
In this Distance/Time graph, the motion is first not moving at 1 m away from the detector. Then walking away from the detector at a constant speed. Next walk towards the detector at a constant speed. Finally, stop moving for the last couple of seconds.
In this Distance/Time graph, The motion is walking towards the detector at a constant speed. Then one stops for a few seconds. Next, walk towards the detector again in a faster constant speed. Then stop for a few seconds. Finally, Walk away from the detector in a constant speed.
In this Distance/Time graph, The motion is walking away from the detector at a constant speed. Then stop moving for a few seconds. Finally, walk away from the detector at a faster constant speed.
In this Velocity/Time graph, The motion is walking away from the detector at a slow speed, but then quickly pick up speed. Then, continuing walking at a constant speed. Next, start walking in towards the detector at a constant speed. Then keep that speed for a few seconds. Finally, stop moving.
In this Velocity/Time graph, the motion is not moving for the first few seconds. Next, start walking away from the detector at a constant speed. Then stop moving again for a few seconds. Finally walk towards the detector at a constant speed.
In this Velocity/Time graph, The motion is to be already moving at a constant speed going away from the detector once it starts recording. Then one will change directions and start moving back toward the detector at a constant speed. Finally one will stop moving all together.
Sunday, October 3, 2010
Motor Lab
We were asked to build motors the other day. We had one day to gather up all the materials needed to build a motor. Luckily, we were able to gather all the materials even though some of them were hard to get.
When we started building the motor, we were given 30 minutes to hammer the 4 four-inch nails into the wood. The nails had to be 2-3cm apart in width and 5-6 cm apart in length. We then sanded the pop can all the way to the point where both sides were silver. Our first problem popped up when we were trying to fit the axel into the cork. Our cork was a bit bigger than the other corks other people had so it took longer to get the axel in. The cork was also a bit rubbery which didn't help us. The second problem with the cork came up right after the first. the copper coil wasn't holding onto the cork tightly enough, and we spent a long time trying to get it to stick. In the end, our motor ended up as a fail. D=
When we started building the motor, we were given 30 minutes to hammer the 4 four-inch nails into the wood. The nails had to be 2-3cm apart in width and 5-6 cm apart in length. We then sanded the pop can all the way to the point where both sides were silver. Our first problem popped up when we were trying to fit the axel into the cork. Our cork was a bit bigger than the other corks other people had so it took longer to get the axel in. The cork was also a bit rubbery which didn't help us. The second problem with the cork came up right after the first. the copper coil wasn't holding onto the cork tightly enough, and we spent a long time trying to get it to stick. In the end, our motor ended up as a fail. D=
Wednesday, September 22, 2010
Right-hand rule #1: Hold the conductor with your right hand. Your thumb should be pointed in the direction of the conventional, or positive current flow. Your fingers should be pointing in the direction of the magnetic field around the conductor.
Right-hand rule #2(for coils): Hold the coiled conductor with the right hand such that the curved fingers point in the direction of conventional or positive current flow. The thumb points in the direction of the magnetic field within the coil. Outside the coil, the thumb represents north end of the electromagnet produced by the coil.
Right-hand rule #2(for coils): Hold the coiled conductor with the right hand such that the curved fingers point in the direction of conventional or positive current flow. The thumb points in the direction of the magnetic field within the coil. Outside the coil, the thumb represents north end of the electromagnet produced by the coil.
Magnetism
A magnetic force is a force that acts from a distance. A magnetic field is the distribution of a magnetic force in the region of a magnet.
A magnet usually contains two magnetic poles, north and south. Similar magnetic poles, like north and north or south and south, repel each other with force. Dissimilar poles, like north and sough, attract each other with force.
Only nickel, iron and cobalt are attracted to magnets so they are known as ferromagnetic metals.
The Domain theory states that all large magnets are made up of many smaller and rotatable magnets, known as dipoles. Dipoles can ineract with other dipoles close by. If dipoles line up, then a small magnetic domain is produced.
Oersted's Principle: Charge moving through a conductor produces a circular magnetic field around the conductor.
A magnet usually contains two magnetic poles, north and south. Similar magnetic poles, like north and north or south and south, repel each other with force. Dissimilar poles, like north and sough, attract each other with force.
Only nickel, iron and cobalt are attracted to magnets so they are known as ferromagnetic metals.
The Domain theory states that all large magnets are made up of many smaller and rotatable magnets, known as dipoles. Dipoles can ineract with other dipoles close by. If dipoles line up, then a small magnetic domain is produced.
Oersted's Principle: Charge moving through a conductor produces a circular magnetic field around the conductor.
Tuesday, September 14, 2010
Resistance, Ohm's Law, and Kirchhoff's Laws
The amount of energy transferred to any device depends on two things:
1. The potential difference of the power supply.
2. The nature of the pathway through the loads that use the electric potential energy.
The amount of current flowing through a resistor changes depending on the amount of energy that's put in the resistor.
A thin wire will have more resistance, while a larger one will have less.
In order to calculate resistance, we use the formula R=V/I. Where R is the resistance in ohms (Ω), V is the potential difference in volts and I is the current in amperes.
The ratio between Voltage against Current is constant and is known as Ohm's Law.
Kirchhoff's Current Law: The total amount of current into a junction point equals the total current that flows out of the same point.
Kirchhoff's Voltage Law: The total of all electric potential decreases in any complete circuit loop is equal to any potential increases in that circuit loop.
Kirchhoff's laws apply to the laws conservation of electric charge and the conservation of energy. To make it short, in any circuit, there is no net gain or loss of electric charge or energy.
1. The potential difference of the power supply.
2. The nature of the pathway through the loads that use the electric potential energy.
The amount of current flowing through a resistor changes depending on the amount of energy that's put in the resistor.
A thin wire will have more resistance, while a larger one will have less.
In order to calculate resistance, we use the formula R=V/I. Where R is the resistance in ohms (Ω), V is the potential difference in volts and I is the current in amperes.
The ratio between Voltage against Current is constant and is known as Ohm's Law.
Kirchhoff's Current Law: The total amount of current into a junction point equals the total current that flows out of the same point.
Kirchhoff's Voltage Law: The total of all electric potential decreases in any complete circuit loop is equal to any potential increases in that circuit loop.
Kirchhoff's laws apply to the laws conservation of electric charge and the conservation of energy. To make it short, in any circuit, there is no net gain or loss of electric charge or energy.
Monday, September 13, 2010
Today, Mr. Chung gave us a prelab to do to prepare for the lab we are going to do tomorrow. We were asked to fill out this chart:
NAME SYMBOL UNIT DEFINITION
Voltage V Volts An electromotive force or
potential difference expressed
in volts.
Current I Amperes A flow of electric charge
through a conductor. The rate
of flow of a charge. Current is
measured in amperes.
Resistance R Ohms A measure of the degree to
which a substance impedes the
flow of electric current induced
by a voltage. Resistance is
measured in ohms.
Power P Watts The rate at which work is done,
expressed as the amount of
work per unit time and
measured watts.
NAME SYMBOL UNIT DEFINITION
Voltage V Volts An electromotive force or
potential difference expressed
in volts.
Current I Amperes A flow of electric charge
through a conductor. The rate
of flow of a charge. Current is
measured in amperes.
Resistance R Ohms A measure of the degree to
which a substance impedes the
flow of electric current induced
by a voltage. Resistance is
measured in ohms.
Power P Watts The rate at which work is done,
expressed as the amount of
work per unit time and
measured watts.
Sunday, September 12, 2010
The Energy Ping-Pong Ball and Parallel/Series Circuits
So last friday, we were given an activity by Mr. Chung. The activity involved these 12 questions we had to answer and an energy ball which Mr. Chung refers to as a ping-pong ball. The ping-pong ball lights up when
Question 1: Can you make the energy ball work? What do you think makes the ball flash and hum?
Yes, we can make the ball work by touching and holding the 2 metal contacts with two of our fingers. What makes the ball light up and hum? Ourselves. Humans are conductors so when we touch the metal contacts, the current flows and the ball lights up.
Question 2: Why do you have to touch both metal contacts to make the ball work?
So that the circuit will be complete and the current can flow through the ball.
Question 3: Will the ball light up if you connect the contacts with any material?
Only materials that are conductors will make the ball work.
Question 4: Which materials will make the energy ball work? Test you hypothesis.
Since the material has to be a conductor, our fingers and metals should make the ball work.
Question 5: This ball does not work on certain individuals, what could cause this to happen?
Those certain individuals most likely have dry skin. In order for the circuit to work, one should have enough mositure in their hands so that the circuit can flow properly.
Question 6: Can you make the energy ball work with your group? Will it work with the class?
Yes, our group was able to connect and make a circuit that allowed the ball to light up.
Question 7: What kind of circuit can you form with the energy ball?
The circuit we made with the one energy ball is a simple circuit.
Question 8: Given two balls (combine with another group) can you create a circuit where both balls light up?
Yes, we were able to connect another ball into the circuit and made both balls light up.
Question 9: What do you think will happen if one person lets go of the other person's hand and why?
The circuit becomes incomplete and both balls will not light up.
Question 10: Does it matter who let's go? Try it.
No, it doesn't matter who let's go because there is only one path in the circuit. Anyone that let's go will break the path and thus the circuit.
Question 11: Can you create a circuit where only one ball lights (both balls must be included in the circuit)?
Yes, but in order to do that, we need to make a parallel circuit.
Question 12: What is the minimum amount of people required to complete this?
Just one. One person can hold each ball in one of their hands with their fingers. If they let go one finger on a ball, that ball will stop working, but the other ball will continue to flash.
So what's the difference between a series circuit and parallel circuit? A series circuit only has one continuous path, while a parallel circuit has more than one path. This means that in a series circuit, if the path becomes broken anywhere in the circuit, the load will instantly stop working. But in a parallel circuit, if the path becomes broken, at least 1 load will work while another would stop working.
Question 1: Can you make the energy ball work? What do you think makes the ball flash and hum?
Yes, we can make the ball work by touching and holding the 2 metal contacts with two of our fingers. What makes the ball light up and hum? Ourselves. Humans are conductors so when we touch the metal contacts, the current flows and the ball lights up.
Question 2: Why do you have to touch both metal contacts to make the ball work?
So that the circuit will be complete and the current can flow through the ball.
Question 3: Will the ball light up if you connect the contacts with any material?
Only materials that are conductors will make the ball work.
Question 4: Which materials will make the energy ball work? Test you hypothesis.
Since the material has to be a conductor, our fingers and metals should make the ball work.
Question 5: This ball does not work on certain individuals, what could cause this to happen?
Those certain individuals most likely have dry skin. In order for the circuit to work, one should have enough mositure in their hands so that the circuit can flow properly.
Question 6: Can you make the energy ball work with your group? Will it work with the class?
Yes, our group was able to connect and make a circuit that allowed the ball to light up.
Question 7: What kind of circuit can you form with the energy ball?
The circuit we made with the one energy ball is a simple circuit.
Question 8: Given two balls (combine with another group) can you create a circuit where both balls light up?
Yes, we were able to connect another ball into the circuit and made both balls light up.
Question 9: What do you think will happen if one person lets go of the other person's hand and why?
The circuit becomes incomplete and both balls will not light up.
Question 10: Does it matter who let's go? Try it.
No, it doesn't matter who let's go because there is only one path in the circuit. Anyone that let's go will break the path and thus the circuit.
Question 11: Can you create a circuit where only one ball lights (both balls must be included in the circuit)?
Yes, but in order to do that, we need to make a parallel circuit.
Just one. One person can hold each ball in one of their hands with their fingers. If they let go one finger on a ball, that ball will stop working, but the other ball will continue to flash.
So what's the difference between a series circuit and parallel circuit? A series circuit only has one continuous path, while a parallel circuit has more than one path. This means that in a series circuit, if the path becomes broken anywhere in the circuit, the load will instantly stop working. But in a parallel circuit, if the path becomes broken, at least 1 load will work while another would stop working.
Thursday, September 9, 2010
Newspaper Tower
The other day, we were making newspaper towers to see which group can make the tallest stable structure. At first, we came up with many different ideas for how we should make the tower, but we didn't seem to agree on which idea we should use. Evantually, we came to a comprimise and made our tower with components from each idea.
The physics of our tower was that the base was to be as big as possible so that it could support the cylindrical newspapers above it. As we got higher and higher though, we realized that our base wasn't big enough, as the tower kept leaning to the side. So, in order to keep the tower standing, we added a coned-shape newspaper under the big base in order to keep the tower standing. This could've worked, but then we saw that the tower was barely able to stand on its own due to the fact that the upper part of the structure was too heavy. We realized this when we were evaluating all the towers that were built in the class. It seems that in order to make a tall structure stable, we should've made our tower's upper part with less weight. Since we were using cylindrical newspaper, the tower has more weight on the top and thus is more prone to falling.
Our tower was pretty muched scrapped at the end, so I don't have a picture to show D=
The physics of our tower was that the base was to be as big as possible so that it could support the cylindrical newspapers above it. As we got higher and higher though, we realized that our base wasn't big enough, as the tower kept leaning to the side. So, in order to keep the tower standing, we added a coned-shape newspaper under the big base in order to keep the tower standing. This could've worked, but then we saw that the tower was barely able to stand on its own due to the fact that the upper part of the structure was too heavy. We realized this when we were evaluating all the towers that were built in the class. It seems that in order to make a tall structure stable, we should've made our tower's upper part with less weight. Since we were using cylindrical newspaper, the tower has more weight on the top and thus is more prone to falling.
Our tower was pretty muched scrapped at the end, so I don't have a picture to show D=
Wednesday, September 8, 2010
Current Electricity and Electrical Potential
An electric current is the flow of charge through an electric circuit. Current is the rate of charge flow and is represented by the symbol I.
The unit that represents current is C/s which is also called an ampere. Current can be calculated by the formula I = Q/t where I is the current in amperes, Q is the charge in coulombs, and t is time in seconds.
An ammeter is a current-measuring device that must be wired so that all current can flow through it. The ammeter must be a good conductor so that no energy is lost when it's added into the circuit.
In Direct Current or DC, current flows in one direction from the power supply, through the conductor and ends at the load. In Alternating Current or AC, the electrons can reverse their direction with the help of electric and magnetic forces.
In a circuit, electric potential difference is the electrical potential energy for each coulomb of charge in a circuit. It is represented by the symbol V. Electric potential energy can be calculated by the formula
V = E/Q. E is energy and Q is the charge. Potential difference can also be called voltage.
Subscribe to:
Posts (Atom)