Sunday, April 18, 2010

April 19

You will be completing two labs today. These must be handed in individually. Your effort is graded on a) your logic, b) your sketches for each question and c) your evidence (data).

Lab 1: Directions are found here. The simulation is located at http://phet.colorado.edu/sims/the-ramp/the-ramp_en.jnlp

Lab 2: The simulation is located at http://phet.colorado.edu/sims/lunar-lander/lunar-lander_en.html Your goal is to create a net force math problem that uses data collected from the lunar lab simulator, with an accompanying force diagram.. This data must be collected as the lunar lander is moving DOWN. If I enter in this data, the lunar lab must not crash.

Andy, you need to read the material on induction in the physics book. Then, go to here and here to test out your ideas.

PHYSICS 1 TEST TOMORROW

Thursday, April 15, 2010

Bungie Barbie

Set up the equipment as shown . Remember that you need to tell the Logger Pro what type of force probe is attached...it will not do so automatically. You can use a motion detector below Barbie to determine Barbie's a(net) (hint: the slope of the v-t graph)
Figure 1


Procedures:

Produce as many different graphs as possible by dropping Barbie with at least 3 different cords(rubber bands, yard, fishing line, tape, or other materials are in the cupboard underneath and between the two sinks) and materials. Describe your procedures in 3-6 sentences.(Rubber bands are in a box under the left side of my desk.

Data / Observation:

Sketch, describe, print or save your graphs for each "jump". Clearly indicate which cord or material was used. Also include information such as the amount of force and the time over which the force was applied. Record any relevant observations you saw during the jump. Autoscaling the jump will help

Calculations:

These will be done tomorrow in class.

Conclusions:

State which cord you believe to be best for bungie jumping. Support your choice with your data.

Questions:

Record any questions that arose in the lab. Include any answers to the questions you may have found.





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Physics 3: Andy, you will be working with 2 sims

http://phet.colorado.edu/simulations/sims.php?sim=Resistance_in_a_Wire

and

http://phet.colorado.edu/simulations/sims.php?sim=Circuit_Construction_Kit_DC_Only

Your house has new thick wiring that has very little resistance. Right click on the bulb and select change value to adjust the resistance of the bulb.

i) (0.5 pts) With the resistance of the bulb at 37 ohms, how much power is going into the bulb? ii) (1 pt) How does this bulb brightness compare to the brightness of the bulb when the resistance of the bulb is 1 ohm? Explain the physics reasoning behind why the bulb brightness changes. iii) (0.5 pts) If you had a 100 Watt bulb plugged into one outlet and a 1500 Watt electric heater plugged into another outlet, how would the resistance change?

b) New heavy duty wires will have only a small resistance. If your house is an older home (i.e. built 100 years ago), the old thin wires will have larger resistance. This increase in resistance in the wiring has several effects. In the simulation, select the developer panel under the options menu and begin increasing the resistance of the wires. You can measure the voltage drop between any two points in the circuit by using the volt meter.

i) (2 pts) Set the bulb resistance to be about 2 ohms. As you increase the resistance in the wires, what changes do you see in (1) the current, (2) where the electrons loose their energy, and (3) the amount of power (energy per second) that is being used by this circuit? (Hint: use all of the visual cues and the tools you have like the volt meter to explore the changes). Be sure to explain the physics reasoning behind why these changes make sense given an increase in the resistance of the wires. ii) (1 pt) Given your observations in the previous question, how would using old thin wires affect the brightness of the bulb and the temperature of the wires compared to using new, thick wires with very little resistance? Explain.


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Kelly, go to http://phet.colorado.edu/simulations/sims.php?sim=Geometric_Optics and do the activity found here