1 / 15

Central Forces – LO3

Central Forces – LO3. Experiment – Central Force and Angular Velocity. Aim To show the relationship between central force and angular velocity. Theory

tashya-stokes
Download Presentation

Central Forces – LO3

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Central Forces – LO3

  2. Experiment – Central Force and Angular Velocity Aim To show the relationship between central force and angular velocity.

  3. Theory In this experiment, the turntable rotates. There must therefore be a centripetal force. This centripetal force will be provided by the hanging mass. Satellite mass Hanging mass

  4. As ω = 2π T Fc = msrω2 Fc = Wh = mhg Theory Therefore: mhg = msrω2 mhg = msr 4π2 T2 g, ms, r and π are all constant. Therefore: mhα1 T2 Confirming this relationship will prove the relationship between central force and angular velocity.

  5. Fc = Centripetal Force g = Acceleration due to gravity mh = Hanging Mass ms = Satellite Mass ω = Angular Velocity r = Radius of satellite mass’ rotation T = Period of rotation Wh = Weight of hanging mass

  6. Gear Apparatus Griffin Air Bearing Satellite mass Hanging mass

  7. Satellite Mass Pulley Voltmeter Gear/Motor Assembly Air Blower Stopwatch Hanging Mass

  8. Method The apparatus was set up as shown, with a 10g mass hung from the pulley. The motor, voltmeter and air blower were all switched on. With the satellite mass at its minimum radius, the gear was set to move the turntable. The voltage was slowly increased, causing the turntable to rotate more quickly. When the hanging mass moved slightly upwards, the timer was started and the time for 10 rotations was recorded.

  9. Method This process was repeated a further five times. The mass was then increased in 10g steps, with the process being repeated six times for each mass. A graph of hanging mass, mh, against 1 was drawn. T2

  10. Time for ten rotations Results

  11. A table of uncertainties should be completed as shown on the next slide. A full set of example calculations (both absolute and percentage) must also be given but only for one set of results (e.g. for 10g). Note – the mass is subject to a manufacturer’s calibration uncertainty of ± 1%. Uncertainties

  12. Uncertainties

  13. Graph A graph of hanging mass, mh, against 1 should be plotted. Error bars should be included, using the values from the uncertainties table. T2

  14. Conclusion The graph of mass against 1/T2 is a straight line passing (almost) through the origin. This confirms the relationship between centripetal force and angular velocity.

  15. Evaluation Why does the graph not pass through the origin? Is the radius constant or was it changing slightly? How could this be overcome? There may be friction in the pulley system meaning all of the weight was not necessarily converted to centripetal force. Anything else?

More Related