Today, Mr. Chung introduced us to a new assignment: CANNONS!
Our main goal is to create a cannon that would shoot the cannonball as far as possible.
In physics terms, we need to build a cannon that would produce the greatest range in the x-axis.
The main factor that determines how far it will go is the angle. A longer barrel would be better because the energy would be applied for a longer period of time; however, it wouldn't work like this for our cannons because our cannonballs are not starting from all the way inside it.
We are only allowed to use 5 pop cans and duct tape. The cannonball is to be made of 2 styrofoam cups tape together to form a closed "cylinder".
Grade 11 Physics Blog
Tuesday, November 30, 2010
Friday, November 26, 2010
Blog 12: Dynamics
In the dynamics unit, there are four major topics: Equilibrium, inclines, pulleys and trains.
Equilibrium
In an equilibrium, the forces cancel each other out to make everything equal. In simpler terms, nothing moves when there is equilibrium.
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Equlibrium problem |
Inclines
There are two kind of incline problems: Kinetic and static. In an incline, there is friction as the object slides down or as it begins to slide down.
Incline problem |
Pulleys
Assumptions:
- set your positives (+ in direction of acceleration)
- no air resistance
- T1 = T2
- 2 systems - 2 FBDs
- acceleration of both systems are same
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Pulleys problem part 1 |
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Pulleys problem part 2 |
Trains
Assumptions:
- no air resistance
- set your positives (+ in direction of acceleration)
- no acceleration in y direction
- cords (between the cars) are weightless
- # of FBDs is equal to number of masses
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Train problem part 1 |
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Train problem part 2 |
You should always write the assumptions, as soon as you draw your FBDs
Saturday, November 6, 2010
Blog 11: PROJECTILE MOTION
What is projectile motion or parabolic motion?
Any body that is given initial velocity and then follows a path determined by the effect of the gravitational acceleration and by air resistance (air resistance is usually neglected in physics because we want to make it easier to calculate everything)
Any body that is given initial velocity and then follows a path determined by the effect of the gravitational acceleration and by air resistance (air resistance is usually neglected in physics because we want to make it easier to calculate everything)
This image shows an example of a parabolic motion/projectile motion |
Gravity (g or sometimes ag) is always set to 9.81m/s2 on Earth
Without the effects of gravity and air resistance, an object would be able to move forever without stopping unless it bumps into something.
Big 5 Equations
Although the big 5 equations were first used for linear problems, we started to use these for projectile motion. Acceleration is always assumed as 9.81m/s2 unless another acceleration is given.
The velocities are split into x-components and y-components. In parabolic motion, the x-component is the same throughout, i.e if it started with a velocity of 2m/s it will end with a final velocity of 2m/s. However, this is not the case for the y-component as the gravity gives the object acceleration. This acceleration means that the velocity will be either increasing or decreasing depending on the direction that the object is traveling in. Going up would slow it down and vice versa. Therefore, when the object is going down, the y-component will increase as will the displacement.
Thursday, October 28, 2010
Blog 10: ROLLERCOASTERS~
Today, we were given our ISUs (Independent Study Units). One of the assignments was to build a rollercoaster, that would be entered into the annual competition at Paramount Canada's Wonderland. This assignment will be a long, difficult one and it will be due on January.
Here is my favourite coaster:
Here is my favourite coaster:
This rollercoaster won for the Artistic Category in 2009 |
Monday, October 25, 2010
Blog 9: Adding or Subtracting Vectors
There are two main ways to go about adding or subtracting vectors:
a) Measure and draw vectors in scale (1cm=1km)
b) Connect the head to tail
c) Resultant is always origin to destination (AYJackson to PMall :P)
d) When you "subtract" vectors, you are actually adding in the opposite direction (12km[N] can be rewritten as -12km[S])
a) Set you positive axes
1. Use a scale diagram
b) Connect the head to tail
c) Resultant is always origin to destination (AYJackson to PMall :P)
d) When you "subtract" vectors, you are actually adding in the opposite direction (12km[N] can be rewritten as -12km[S])
e) Use a protractor to measure the angle in accordance to North and South.
2. Add or subtract by components
b) Break all vectors into two components (x and y)
c) Solve for ∑x and ∑y (summation of x and y)
d) Use Pythagorean Theorem to add the two sums of components (∑x and ∑y)
e) Use trigonometry to solve for angle
SOH → sinθ = opp/hyp
CAH → cosθ = adj/hyp
TOA → tanθ = sinθ/cosθ = opp/adj
Tuesday, October 12, 2010
Blog 8: Position-Time & Velocity-Time Graphs
Position vs Time Graphs
Stayed for 1 second at a distance of 1m
Walked away for 2.5 m in 2 seconds
Stayed at 2.5 m for 3 seconds
Walked approximately 1 m towards in 1.5 seconds
Stayed for 2.5 seconds at 1.5 m
Walked towards 1.5 m from 3 m for 3 seconds
Stayed for 1 second
Walked towards 1 m for 1 second
Stayed for 2 seconds
Walked away 2.5 m for 3 seconds
Walked away 1 m for 3.5 seconds
Stayed for 3 seconds
Walked away 1.4 m for 3.5 seconds
---------------------------------
Velocity vs Time Graphs
Stayed for 2 seconds
Walked towards at 0.5m/s for 3 seconds
Stayed for 2 seconds
Walked backwards at 0.5m/s for 3 seconds
Speed up from 0 m/s to 0.5m/s for 4 seconds
Walked at 0.5m/s for 2 seconds
Walked backwards at 0.4m/s for 3 seconds
Stayed for 1 second
Walked at 0.36 m/s for 3 seconds
Walked backwards at 0.4m/s for approximately 3.75 seconds
Stayed for approximately 3 seconds
Friday, October 1, 2010
Blog 7: Building an Electric Motor
On Wednesday, Mr. Chung gave an interesting assignment to the class: We were to create our own electric motors. He asked us to bring our own materials if we could.
Materials:
· paper clips
· cork
· pop can
· sandpaper
· thumbtacks
· stick (axel)
· nails
· pins (commutator)
· scissors
Mr. Chung provided us with most of the materials, including a hammer. He gave us short instructions and hints throughout the lab, such as how the coils should be in parallel to the nails, not perpendicular. If you were to coil them perpendicular
This lab was very effective, for me anyway, because it was a hands-on activity. I got much more out of it then I would have from listening to how it works.
Eddie and I completed our electric motor and presented it to Mr. Chung. He hooked the two pop can sheets (brushes) with 2 wires, which were connected to a large battery. He switched the power source on and our cork started turning very quickly, only slowing down once every few seconds.
On Friday, we took our motor for another spin so we could film it, but it didn’t work as well as the day before. It still worked though…
Here is our video of the motor:
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