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| 183_notes:examples:finalloccf [2014/07/11 03:02] – caballero | 183_notes:examples:finalloccf [2014/07/14 17:08] (current) – caballero |
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| ===== Example: Predicting the location of an object undergoing constant force motion ===== | ===== Example: Predicting the location of an object undergoing constant force motion ===== |
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| The fan cart in the video below is observed to [[183_notes:acceleration|accelerate]] uniformly to the right. The air exerts a [[183_notes:constantf|constant force]] on the blades that is around 0.45N. Determine the how far the has traveled after 2.2s if the cart starts from rest. | The fan cart in the video below is observed to [[183_notes:acceleration|accelerate]] uniformly to the right. The air exerts a [[183_notes:constantf|constant force]] on the blades that is around 0.45N. Determine the how far the fan cart has traveled after 2.2s if the cart starts from rest. |
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| === Facts ==== | === Facts ==== |
| * the force applied by the track (directly upward) | * the force applied by the track (directly upward) |
| * a frictional forces and air resistance that resist the motion | * a frictional forces and air resistance that resist the motion |
| * The acceleration due to gravity is 9.8 $\dfrac{m}{s^2} and is directed downward. | * The acceleration due to gravity is 9.8 $\dfrac{m}{s^2}$ and is directed downward. |
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| === Lacking === | === Lacking === |
| === Approximations & Assumptions === | === Approximations & Assumptions === |
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| * Over the interval that we care about it, we will assume the net force is doesn't change. That is, the cart experiences [[183_notes:constantf|constant force motion]]. | * Over the interval that we care about it, we will assume the net force doesn't change. That is, the cart experiences [[183_notes:constantf|constant force motion]]. |
| * As a result, the motion occurs only in the horizontal direction. | * As a result, the motion occurs only in the horizontal direction. |
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| We can compute this displacement, | We can compute this displacement, |
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| Δxcart=(0ms)(2.2s)+120.45N0.3kg(2.2s)2 | $$\Delta x_{cart} = (0 \dfrac{m}{s}) (2.2 s) + \dfrac{1}{2}\dfrac{0.45 N}{0.3kg}(2.2s)^2 = 3.6 m$$ |
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