Frictional Force Experiment
Posted: Fri Nov 27, 2015 11:34 am
I recently did the following experiment for AP Physics 2:
Your goal is to determine the force of friction between the plunger and walls of a plastic syringe through the analysis of the work done during a thermodynamic process. You must also develop and deploy a different method that can be used to validate your results.
My group measured the pressure inside a syringe at room temperature. Then we boiled a beaker of water, and put the syringe inside the boiling water. We extended the syringe so that it added a certain amount of volume, then waited for the pressure to catch up with the pressure it was at room temperature. This way the pressure is kept constant. We measured the length we moved the syringe as well. This is our data from trial 1:
Pressure (inside the syringe) at room temperature: 100 kPa
Temperature at room temperature: 22.7 C
Temperature in hot water: 93.4 C
Volume added to the syringe by extension: +14 mL
Length syringe was extended: 4.45 cm
For the second part of the experiment, to validate the results, we used a spring scale to pull downwards on the syringe until it was moving at a constant speed, then the applied force was recorded: 1200 N. Is there any way to find the frictional force from that? Remember, this is a separate procedure from the one above, and will be used to calculate the error.
Is there any way to calculate the frictional force from this data? I feel like we are missing something, but if there is a way to calculate it just from what was recorded (and yes, this is all we have) then any help would be greatly appreciated.
Your goal is to determine the force of friction between the plunger and walls of a plastic syringe through the analysis of the work done during a thermodynamic process. You must also develop and deploy a different method that can be used to validate your results.
My group measured the pressure inside a syringe at room temperature. Then we boiled a beaker of water, and put the syringe inside the boiling water. We extended the syringe so that it added a certain amount of volume, then waited for the pressure to catch up with the pressure it was at room temperature. This way the pressure is kept constant. We measured the length we moved the syringe as well. This is our data from trial 1:
Pressure (inside the syringe) at room temperature: 100 kPa
Temperature at room temperature: 22.7 C
Temperature in hot water: 93.4 C
Volume added to the syringe by extension: +14 mL
Length syringe was extended: 4.45 cm
For the second part of the experiment, to validate the results, we used a spring scale to pull downwards on the syringe until it was moving at a constant speed, then the applied force was recorded: 1200 N. Is there any way to find the frictional force from that? Remember, this is a separate procedure from the one above, and will be used to calculate the error.
Is there any way to calculate the frictional force from this data? I feel like we are missing something, but if there is a way to calculate it just from what was recorded (and yes, this is all we have) then any help would be greatly appreciated.