The pennies before the vinegar/salt bath:
And these are the pennies after:
Thursday 12 January 2012
Lab Pictures
For the portfolio, I had to do a lab, and that's in the binder I'm handing in. But I wanted to put in some pictures I took of the pennies. So here they are:
The pennies before the vinegar/salt bath:
And these are the pennies after:
The pennies before the vinegar/salt bath:
And these are the pennies after:
Monday 2 January 2012
Physics #2
For this post, I'm going to post questions from the textbook
Page 376
Question 12: The traffic sign at the beginning of a school zone reads "30 km/h" Is this sign a 'speed zone' sign or a 'velocity zone' sign? explain your answer.
Answer: To me, the sign in a 'speed zone' sign. This is because the sign only tell the speed, and not the direction the car needs to go.
Question 16: The SI unit for average speed or average velocity is m/s. What is another common unit used for these two concepts?
Answer: Another common unit is km/h
Page 377
Question 20: A girl rides her bike 420m south in time of 47s. What is her average velocity?
Answer: V=d/t, V=420/47, V=9m/s
Page 391
Question 8: A) If the acceleration is in the same direction as the velocity, what happens to the speed of an object
Answer: The speed of the object will increase
B) If the acceleration is in the opposite direction to the velocity, what happens to the speed of an object?
Answer: The speed of an object will decrease.
Question 9: A car traveling forward at 25m/s stops and backs up at 4m/s
A) What is the car's change in velocity?
Answer: The change in velocity is 21m/s
B) What is the direction of the car's acceleration?
Answer: Backward
Page 397
Question 1: A car starting from rest accelerates uniformly to 15m/s [E] in 5s. What is the car's acceleration?
Answer: A=^V/t, A=15m/s / 5s, A=3m/s2 [E]
Page 405
Question 2: What does the slope of a velocity-time graph represent?
Answer: The slope represents the acceleration of an object.
Question 6: In the absence of air resistance, what is the magnitude and direction of the acceleration due to gravity near the surface of Earth?
Answer: The acceleration due to gravity is 9.8m/s2 downward.
Question 8: What is the acceleration of a golf ball that is accelerated uniforly from rest 55m/s forward in 0.00045s?
Answer: A=^V/t, A=55/0.00045, A=12222.23m/s2
I thought these questions were important to the unit because it shows air resistance, gravity, the slope, and equations. If I didn't know how to factor in all of these, and to do the equations, I wouldn't have been able to pass the unit, or understand what my teacher was talking about, and luckily I did.
Page 376
Question 12: The traffic sign at the beginning of a school zone reads "30 km/h" Is this sign a 'speed zone' sign or a 'velocity zone' sign? explain your answer.
Answer: To me, the sign in a 'speed zone' sign. This is because the sign only tell the speed, and not the direction the car needs to go.
Question 16: The SI unit for average speed or average velocity is m/s. What is another common unit used for these two concepts?
Answer: Another common unit is km/h
Page 377
Question 20: A girl rides her bike 420m south in time of 47s. What is her average velocity?
Answer: V=d/t, V=420/47, V=9m/s
Page 391
Question 8: A) If the acceleration is in the same direction as the velocity, what happens to the speed of an object
Answer: The speed of the object will increase
B) If the acceleration is in the opposite direction to the velocity, what happens to the speed of an object?
Answer: The speed of an object will decrease.
Question 9: A car traveling forward at 25m/s stops and backs up at 4m/s
A) What is the car's change in velocity?
Answer: The change in velocity is 21m/s
B) What is the direction of the car's acceleration?
Answer: Backward
Page 397
Question 1: A car starting from rest accelerates uniformly to 15m/s [E] in 5s. What is the car's acceleration?
Answer: A=^V/t, A=15m/s / 5s, A=3m/s2 [E]
Page 405
Question 2: What does the slope of a velocity-time graph represent?
Answer: The slope represents the acceleration of an object.
Question 6: In the absence of air resistance, what is the magnitude and direction of the acceleration due to gravity near the surface of Earth?
Answer: The acceleration due to gravity is 9.8m/s2 downward.
Question 8: What is the acceleration of a golf ball that is accelerated uniforly from rest 55m/s forward in 0.00045s?
Answer: A=^V/t, A=55/0.00045, A=12222.23m/s2
I thought these questions were important to the unit because it shows air resistance, gravity, the slope, and equations. If I didn't know how to factor in all of these, and to do the equations, I wouldn't have been able to pass the unit, or understand what my teacher was talking about, and luckily I did.
Info
Ok, so as I'm not going to be able to post some of the stuff that I have to have in the portfolio, such as the lab and the title page, I'm going to hand those in in a booklet. Just letting you people know :)
Sunday 1 January 2012
Physics #1
For the first post on the physics unit, I'm going to write down all of the key words for chapter 8 and chapter 9
Acceleration: the rate at which an object changes it's velocity
Acceleration Due To Gravity:...in the absence of gravity; the value of acceleration due to gravity near the surface of the Earth is approximately 9.8 m/s2 downward
Air Resistance: a friction-like force that opposes the motion of objects that move through the air.
Average Acceleration: average rate at which an object changes it's veloctiy shown by the slope of a velocity-time graph.
Average Velocity: the rate of change in position for a time interval.
Change In Velocity: change the occurs when the speed, the direction, or both of an object calculated by subtracting the initial velocity from the final velocity.
Constant Acceleration: velocity changing at a constant rate
Deceleration: acceleration that is opposite to the direction of motion; a decrease in speed.
Displacement: the straight line distance and direction from one point to another.
Distance: a scalar quantity that describes the length of a path between two points or location.
Gravity: attractive force between two or more masses
Position: a vector quantity that describes a specific point relative to a reference point.
Position-time graph: a graph of an objects position during corresponding time intervals.
Scalars: quantities that only have magnitude.
Slope: the direction of a line on a graph.
Uniform Motion: traveling in equal displacement in equal time intervals.
Vectors: quantities that have both magnitude and direction
Velocity: the displacement of an object during a time interval divided by the time interval
If I didn't know what these words meant, I wouldn't have been able to understand the unit...at all. But I do, so I did.
Acceleration: the rate at which an object changes it's velocity
Acceleration Due To Gravity:...in the absence of gravity; the value of acceleration due to gravity near the surface of the Earth is approximately 9.8 m/s2 downward
Air Resistance: a friction-like force that opposes the motion of objects that move through the air.
Average Acceleration: average rate at which an object changes it's veloctiy shown by the slope of a velocity-time graph.
Average Velocity: the rate of change in position for a time interval.
Change In Velocity: change the occurs when the speed, the direction, or both of an object calculated by subtracting the initial velocity from the final velocity.
Constant Acceleration: velocity changing at a constant rate
Deceleration: acceleration that is opposite to the direction of motion; a decrease in speed.
Displacement: the straight line distance and direction from one point to another.
Distance: a scalar quantity that describes the length of a path between two points or location.
Gravity: attractive force between two or more masses
Position: a vector quantity that describes a specific point relative to a reference point.
Position-time graph: a graph of an objects position during corresponding time intervals.
Scalars: quantities that only have magnitude.
Slope: the direction of a line on a graph.
Uniform Motion: traveling in equal displacement in equal time intervals.
Vectors: quantities that have both magnitude and direction
Velocity: the displacement of an object during a time interval divided by the time interval
If I didn't know what these words meant, I wouldn't have been able to understand the unit...at all. But I do, so I did.
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