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Physics 114 – Lecture 5. §2.7 Falling Objects Galileo, any object at surface of earth in free fall accelerates at a constant rate a = g = 9.80m/s 2 vertically downwards ≡ towards the center of the earth – experimental observation.
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Physics 114 – Lecture 5 §2.7 Falling Objects Galileo, any object at surface of earth in free fall accelerates at a constant rate a = g = 9.80m/s2 vertically downwards ≡ towards the center of the earth – experimental observation. Air resistance? Must be eliminated in order for free fall to occur. L5-s1,2
Physics 114 – Lecture 5 • Since a = const we may use our equations for motion with a = constant • Choose axes as shown → a = -g • = -9.80 m/s2thatis directed downwards • Our equations → with v, v0 in the vertical direction, • v = v0 - gt no y, y0 • y = y0 + v0t - ½ gt2 no v • v2 = v02 – 2g(y – y0) no t • vave = (v + v0)/2 and y – y0 = vave t no g • Be careful when using the last equations • Let us work some examples y 0 x L5-s2,2