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Unformatted text preview: January 13, 2009 PHY2054 Discussion-Spring 09 Warm Up Quiz (Physics 1 Review) Name: UFID: **1. (0pt) Tim Tebow throws a football toward Percy Harvin with an initial speed of 25.0 m/s at an angle of 30.0 above the horizontal. At that instant, Percy is 40.0 m from Tim. In what direction and with what constant speed should Percy run in order to catch the football at the level at which it was thrown? The horizontal and vertical components of the initial velocity are given by v 0x = v cos = 25cos30 = 21.7 m/s, v 0y = v sin = 25sin30 = 12.5 m/s When the ball comes back to its original height, vertical displacement is zero. Thus the flight time and the horizontal range are 0 = v 0y t-(1/2)gt 2 0 = t(v 0y-(1/2)gt) t = 2v 0y /g = 212.5/9.8 = 2.55 s x = v 0x t = 21.72.55 = 55.3 m Percy needs to run a distance of d = 55.3 40 = 15.3 m away from Tim with a constant speed of v = d/t = 15.3/2.55 = 6.00 m/s ***2. (0pt) A luggage carousel at an airport has the form of a section of a large cone, steadily ***2....
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