4.1.1.P7
My 11 year old grandson, Danny, got a remote controlled car for his birthday. His older brother, Jay, has a set of physics tools, including a sonic ranger. Jay is a computer jockey and has figured out how to make the sonic ranger program show any coordinate system he wants. He has chosen the positive direction to be away from the ranger and the origin to be a meter in front of the ranger as shown. (He knows to connect the ranger to the computer and tip its face perpendicular so it measures correctly.)
Danny starts the car moving forward slowly. Jay turns on the sonic ranger. Then Danny speeds the car up, slows it down, and finally puts it into reverse, speeding it up going backward. From the graphs below, choose one graph, which, if it had the proper units on the vertical axis, could represent what the computer would show for the list of variables below. If none of them could work for the motion described, put N in the box and sketch what the correct graph would look like next to the box.
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1. The position of the car. 2. The velocity of the car. 3. The acceleration of the car. 4. The net force acting on the car. 5. Do the graphs you have chosen describe a single motion? |
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Joe Redish 10/3/13