Rocket Quiz
Went over velocity vs time graph for bouncing ball.
Reviewed velocity vs time graphs for rockets.
Answered any questions from the rest of the linear motion problem set.
Students counted off and worked on end-of-chapter questions.
Thursday, February 26, 2009
Thursday, Feb 19, 2009
Collected RA 2.5
Rocket Day!! Lab Write-up due on Monday
Explained Rocket Lab procedure and safety precautions and then went out and shot rockets.
Rocket Day!! Lab Write-up due on Monday
Explained Rocket Lab procedure and safety precautions and then went out and shot rockets.
Wednesday, February 18, 2009
Wednesday, Feb 18, 2009 - Block 2
Checked temperature - too cold for rockets. Only 42 deg F. Will shoot rockets tomorrow if weather improves and it gets warmer.
Collected RA 2.3, RA 2.4, and CD 2.2
Handed back RA 2.2 and answered any questions.
Answered questions and worked a few problems from the linear motion problem sheet.
Showed graphical approach to linear motion problems.
Handed out RA 2.5, due tomorrow.
Collected RA 2.3, RA 2.4, and CD 2.2
Handed back RA 2.2 and answered any questions.
Answered questions and worked a few problems from the linear motion problem sheet.
Showed graphical approach to linear motion problems.
Handed out RA 2.5, due tomorrow.
Tuesday, Feb 17, 2009 - Block 2 - IB Physics 1
Collected RA 2.2
Explained and handed out Concept Development 2.2. It is due for the last time on Monday.
Reviewed Sus-It-Out Method for solving problems in linear motion with constant acceleration. Showed how to use the Sus-It-Out method to solve rocket problems.
Derived equations of motion for constant acceleration.
Gave students the problem sheet on linear motion problems. Asked them to solve the problems on the first page (problems 1-12).
Gave students time in class to work on them.
If it is nice tomorrow, we will shoot rockets.
Explained and handed out Concept Development 2.2. It is due for the last time on Monday.
Reviewed Sus-It-Out Method for solving problems in linear motion with constant acceleration. Showed how to use the Sus-It-Out method to solve rocket problems.
Derived equations of motion for constant acceleration.
Gave students the problem sheet on linear motion problems. Asked them to solve the problems on the first page (problems 1-12).
Gave students time in class to work on them.
If it is nice tomorrow, we will shoot rockets.
Friday, February 13, 2009
Friday, Feb 13, 2009 - Block 2
Gave students average speed problem to work on.
A plane flies 200 miles at a speed 80 miles/hr. It then immediately turns around and flies back at a speed of 120 miles/hr.
What is the total distance traveled?
What is the displacement?
What is the average speed?
What is the average velocity?
Most students gave the average speed as 100 miles/hr but it should be 96 miles/hr since average speed = total distance/total time.
Gave students the bike and bee problem. There are often many ways of doing a problem, some easy, some hard. Think about the problem and choose an easy way - life is too short.
Went over Seattle example.
Showed that we get the equations d = v * t, v = d/t, t = d/v
Mentioned that this is the average speed since you probably were not traveling at the same constant speed for the entire trip.
A rate is some quantity divided by time. V is a rate, the rate at which you cover distance.
Went around the room and asked students to give additional examples of rates, something that changes with time.
Hourly wage is the rate at which you make money. The amount you make is the rate * time. Amount you have = amount you started with + rate * time.
Suppose you have a job that pays $10/hr. This is the rate at which you make money.
Suppose the next year, they pay you $15/hr, and the year after that, $20/hr. Note that your hourly wage is increasing by $5/hr/year. This is the rate of a rate.
Did examples of driving a car, speeding up from 45 mph to 55 mph in 2 seconds. The rate at which you increase speed is (vf-vi)/t = 5 miles/hr/sec.
We call this change in velocity/time (the rate at which you change velocity) the acceleration. Acceleration is any change in VELOCITY/time. You are accelerating if you speed up, slow down, or change direction.
If the acceleration is in the same direction as the velocity, you speed up.
If the acceleration is opposite in direction to the acceleration, you slow down.
If the acceleration is perpendicular to the velocity, you don't change your speed, but you do change direction.
Driving the car example. You FEEL acceleration but you do not FEEL constant velocity.
Near the surface of the Earth, the acceleration of gravity is about 10 m/s/s down. This is the rate at which a dropped object picks up speed.
Did picket fence demo to show not only how to use the computer and how a photogate works but also how to measure the acceleration of gravity. We measured about 9.76 m/s/s.
Went around the room and students answers how fast an object would be traveling after falling for a given time.
vf = vi + a * t which we got from the definition of acceleration.
Did several examples of dropping an object, throwing an object up, throwing an object down.
Referred back to the Seattle Example: d = v* t
This gives the displacement, but what do we use for v since it is not constant?
If the acceleration is constant, as it is near the surface of the Earth, then we can use vavg = (vi+vf)/2
d = vavg*t = (vi+vf)/2 * t
Did several examples of finding displacement for dropping, throwing up, or throwing down.
Handed out RA 2.2, 2.3, 2.4
RA 2.2 is due on Tuesday, RA 2.3, 2.4 are due on Wednesday
A plane flies 200 miles at a speed 80 miles/hr. It then immediately turns around and flies back at a speed of 120 miles/hr.
What is the total distance traveled?
What is the displacement?
What is the average speed?
What is the average velocity?
Most students gave the average speed as 100 miles/hr but it should be 96 miles/hr since average speed = total distance/total time.
Gave students the bike and bee problem. There are often many ways of doing a problem, some easy, some hard. Think about the problem and choose an easy way - life is too short.
Went over Seattle example.
Showed that we get the equations d = v * t, v = d/t, t = d/v
Mentioned that this is the average speed since you probably were not traveling at the same constant speed for the entire trip.
A rate is some quantity divided by time. V is a rate, the rate at which you cover distance.
Went around the room and asked students to give additional examples of rates, something that changes with time.
Hourly wage is the rate at which you make money. The amount you make is the rate * time. Amount you have = amount you started with + rate * time.
Suppose you have a job that pays $10/hr. This is the rate at which you make money.
Suppose the next year, they pay you $15/hr, and the year after that, $20/hr. Note that your hourly wage is increasing by $5/hr/year. This is the rate of a rate.
Did examples of driving a car, speeding up from 45 mph to 55 mph in 2 seconds. The rate at which you increase speed is (vf-vi)/t = 5 miles/hr/sec.
We call this change in velocity/time (the rate at which you change velocity) the acceleration. Acceleration is any change in VELOCITY/time. You are accelerating if you speed up, slow down, or change direction.
If the acceleration is in the same direction as the velocity, you speed up.
If the acceleration is opposite in direction to the acceleration, you slow down.
If the acceleration is perpendicular to the velocity, you don't change your speed, but you do change direction.
Driving the car example. You FEEL acceleration but you do not FEEL constant velocity.
Near the surface of the Earth, the acceleration of gravity is about 10 m/s/s down. This is the rate at which a dropped object picks up speed.
Did picket fence demo to show not only how to use the computer and how a photogate works but also how to measure the acceleration of gravity. We measured about 9.76 m/s/s.
Went around the room and students answers how fast an object would be traveling after falling for a given time.
vf = vi + a * t which we got from the definition of acceleration.
Did several examples of dropping an object, throwing an object up, throwing an object down.
Referred back to the Seattle Example: d = v* t
This gives the displacement, but what do we use for v since it is not constant?
If the acceleration is constant, as it is near the surface of the Earth, then we can use vavg = (vi+vf)/2
d = vavg*t = (vi+vf)/2 * t
Did several examples of finding displacement for dropping, throwing up, or throwing down.
Handed out RA 2.2, 2.3, 2.4
RA 2.2 is due on Tuesday, RA 2.3, 2.4 are due on Wednesday
Thursday, Feb 12, 2009 - Block 2
Intro to motion lecture
Talked about the Greek view of the universe and how they thought force was needed to maintain motion. They could not imagine a world without air resistance or without friction. Galileo could.
Showed video clip of dropping a coin and feather in a vacuum, and also dropping hammer and feather on Moon.
Demo of dropping ball bearings in soap.
Galileo's thought experiments for air resistance and inertia.
Defined distance, displacement, speed, average speed, velocity, average velocity.
Gave students time in class to work on RA 2.1
Talked about the Greek view of the universe and how they thought force was needed to maintain motion. They could not imagine a world without air resistance or without friction. Galileo could.
Showed video clip of dropping a coin and feather in a vacuum, and also dropping hammer and feather on Moon.
Demo of dropping ball bearings in soap.
Galileo's thought experiments for air resistance and inertia.
Defined distance, displacement, speed, average speed, velocity, average velocity.
Gave students time in class to work on RA 2.1
Wednesday, Feb 11, 2009 - Block 2
Handed out answers to unit conversion worksheet.
Took students to the computer lab 448. There they did the Excel Spreadsheet lab. When they got the first part done, they put in the data values for their Graphing Round Objects Lab and printed out the graph. On the graph they showed the slope and the uncertainty in the slope they got from the Linest function in Excel.
If they finished, they had the option to continue with the exercises in finding uncertainties using the Max Min method and the Method of Relative Uncertainties.
Students handed back their original labs and their computer generated graphs for the Graphing Round Objects Lab.
Took students to the computer lab 448. There they did the Excel Spreadsheet lab. When they got the first part done, they put in the data values for their Graphing Round Objects Lab and printed out the graph. On the graph they showed the slope and the uncertainty in the slope they got from the Linest function in Excel.
If they finished, they had the option to continue with the exercises in finding uncertainties using the Max Min method and the Method of Relative Uncertainties.
Students handed back their original labs and their computer generated graphs for the Graphing Round Objects Lab.
Subscribe to:
Posts (Atom)