Computer Lab Graphing for Pendulum Lab

Before you begin, you should calculate the averages and uncertainties for all of your trials for period.  In addition, you should divide by the number of swings so that your average periods are for just one swing.

Make 2 graphs:  one of Period vs. Mass and another of Period vs. String Length. Besides all of the usual components of a good graph, include uncertainties in your graphs, draw a line of best fit (unclick "connect points"), and include an annotation. 

Finally, look at the String Length Graph and determine the shape of the line.  If it looks like a straight line, you may simply find the slope of the line.  If it looks like an exponential (x squared), square the lengths of the string and enter those as an additional column in your data table.  If it looks like 1/x, calculate 1/length for your 5 lengths and enter that in an additional column.  Whatever the function, do that function to the length data and enter it as an additional column.

Now make a 3rd graph that plots period vs. the modified data (the additional column).  If you picked the correct function, this technique should "straighten out" the line and you can find the slope of that new line.  You will now be able to write a "master equation" for the period of the pendulum.  For example if your original length data looked like an x squared function and the slope of your 3rd graph is 7.14, your master equation will look like this:   T  =  7.14 L^2 (only string length is squared).  Finally, you can check your "master equation" to make sure that it actually works for your data for period and string length.  Good luck!

Answers to 7+8 Review for test on Friday 2/24

 15.  9500 N     16.  1.0 Nm     17.  0.30 m       18.  0.44 m       19.  18 kg m^2       20.  0.25 kg m^2/s      21.  25 kgm^2/s     22.  1.9 rad/s

2/22-3/5/2012

• Wed 2/22:  Hand-out 7+8 Review and work on it.  Introduce Machine Project and work on it.
• Friday 2/24:  Demonstrate Machines.  Turn in 7+8 Review.  Take 7+8 Test.
• Tuesday 2/28:  Introduce Simple Harmonic Motion.  Pendulum Lab.
• Thursday 3/1:  Computer Lab to do Pendulum Graphs.  Introduce Spring Inquiry Lab.  Write problem statement, background, hypothesis, variables, procedure.
• Monday 3/5:  Take data for Spring Inquiry and process data.  Bring in full write-up to be color-marked on Friday 3/9.
• 
  

Rolling Balls Lab Write-Up

This is what you need for the Rolling Balls Lab, due Wednesday 2/22:
1)  Neat well-labeled data table with units (you may include calculated values)  Make sure that you include all 5 trials and the average for each object
2)  Calculations:  Final Velocity, Final Angular Speed, Potential Energy, Translational KE, Rotational KE.  All values should be calculated for each object, but you only need to show a sample calculation for each type once
3)  Check conservation of energy.  For each object, complete the equation:  mgh = 1/2 mv^2 + 1/2Iw^2
4)  Answer Questions A, B, C, D.  Make sure that you use data to back yourself up!

February 6-February 17

Can you believe it is the beginning of the 2nd semester?   For all of you, that means a fresh start.  2nd semester is generally easier than 1st semester conceptually, but you will still need to do the homework and labs to be successful.  If you find yourself struggling, ask for help early and come in for FLEX if needed.   Check the website and get caught up ASAP if you are absent. 

Mon 2/6:  Hand Back Final Exams, Look at them, and Recollect.  2nd semester survey.  Circular Motion Lab.
Wed 2/8:  Turn in Circular Motion Lab.  Centripetal Force Problems.  Torque Lab.
Fri  2/10:  Check off Centripetal Force Problems.  Torque Problems.  Momentum of Inertia and Newton's 2nd Law for Angular Motion.
Tues 2/14:  Check off Newton's 2nd Law Problems and go over.  Conservation of Angular Momentum.  Video clips.  Turn table demonstration.  Problems.
Thurs 2/16:  Check off Angular Momentum Problems and go over.  Conservation of Energy.  Rolling Balls Lab.  Simple Machines.
Fri 2/17:  Senior Seminar Day.  Short classes.  Simple Machine Project.
Mon 2/20:  No School.  President's Day!