Lectures on Physics has been derived from Benjamin Crowell's Light and Matter series of free introductory textbooks on physics. See the editorial for more information.... |
Home Newtonian Physics Acceleration and Free Fall Examples Saving an old lady | ||
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Saving an old ladyYou are trying to pull an old lady out of the way of an oncoming truck. You are able to give her an acceleration of 20 m/s2. Starting from rest, how much time is required in order to move her 2 m? First we organize our thoughts: Variables given: Δx, a, vo Variables desired: Δt Irrelevant variables: vf Consulting the triangular chart above, the equation we need is clearly Δx = voΔt + 1/2 aΔt2, since it has the four variables of interest and omits the irrelevant one. Eliminating the vo term and solving for Δt gives
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Home Newtonian Physics Acceleration and Free Fall Examples Saving an old lady |