We have been using a fan to exert a force on a cart placed on a level, low-friction track. You have seen that, when the fan is operating as shown, and the cart is released near the detector, the cart accelerates to the right, which we have defined as the positive direction. Remember the resulting velocity vs. time graph of this motion? Now, what happens when the fan is operating as before (pushing the cart away from the motion detector) but the cart is placed on the other end of the track and given a momentary, push towards the motion detector?
1) What do you predict a graph of velocity vs. time will look like for this experiment after the cart has been pushed towards the detector? Draw on the following graph your prediction for the velocity of the cart over time (after the initial push to the left).
2) Explain in words why you drew your graph as you did.
3) What do you predict a graph of acceleration vs. time will look like for this experiment after the cart has been pushed towards the detector? Draw your prediction on the following graph.
4) Explain in words why you drew your graph as you did.
Now we will undertake the experiment. Watch and see what happens.
5) Did the results agree with your prediction for velocity vs. time? Describe what actually happened and draw and label the velocity-time graph that was observed. If your prediction was correct, explain why below. If not, explain why you weren't correct.
6) Did the results agree with your prediction for acceleration vs. time? Describe what actually happened. Draw and label the acceleration-time graph that was observed. If your prediction was correct, explain why below. If not, explain why you weren't correct.
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