Uses toy car, rulers
See also Pictures related to Straps and Toy Cars
Set the toy car on a smooth level surface and give it a poke with your finger, so that it coasts a foot or so before coming to rest.
Use your 8-count to estimate how long it takes the car to come to rest, starting at the end of the poke. Also measure how far the car travels.
Report your results:
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22cm-1.98sec
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Repeat, with the car traveling in the opposite direction:
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21cm-2.16sec
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Use the TIMER to measure the time interval between the end of the 'poke' and coming to rest. Measure also the distance the car traveled, which will almost certainly be different than the distance it traveled on your previous 'poke'. If not, give it another try. The distance should differ from the previous by at least 5 centimeter.
Report your results:
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45cm-2.90sec
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Repeat, with the car traveling in the opposite direction:
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42.5cm-2.75sec
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Determine the slope of a smooth ramp on which the car, when given a slight poke, will move down the ramp at a constant velocity. The cover of a textbook would make a good smooth surface, as would the foam rectangle enclosed in lab packages (in-class students might not have the foam rectangle, in which case a textbook would be fine).
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4cm-3.75cm=.25cm(rise)/28cm(length book)= 0.0089
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Analysis:
As always, include sample calculations and explanations.
Based on each of your trials determine the average velocity of the car for the interval from 'poke' to rest:
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Based on the assumption that the car's acceleration on any given trial is constant, determine its initial velocity for each trial:
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Using your information, find the car's acceleration for each trial:
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What do you think the car's actual acceleration is on the surface you used, based on your results, and with what uncertainty? Give your result in the format illustrated by the example '130 cm/s^2 +- 20 cm/s^2'. Explain how you estimated your uncertainty.
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What do you think is the percent uncertainty in your TIMER results? What percent uncertainty would this imply for your acceleration?
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If you multiply the slope on which the car maintained constant velocity by the acceleration of gravity you should get a result close to the acceleration of the car. Is this the case?
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