. You are standing at the edge of a cliff, for some reason. You toss a rock up i

Question

. You are standing at the edge of a cliff, for some reason. You toss a rock up in the air at a speed of 32.0 m/s. Just as you release the rock, you see a bird flying overhead (oops!). Fortunately the rock just misses the confused bird. a) If you estimate that the bird is 12.0 m above you, how fast was the rock moving when it passed him? b) How much time would have elapsed between the instant you released the rock and the time it passed the height 12.0 m above you? c) In theory, there are actually two possible correct answers to part b. Explain why there are two answers.

Explanation / Answer

a)

v^2 - u^2 = -2*g*h

V^2 = 32^2 -2*9.8*12

V = 28.085 m/s at 12 m height

b)

s =ut -1/2gt^2

12 = 32*t -0.5*9.8*t^2

solving gives two values for t

part c : two values for part b is because the rock will be at that height while going up and again when it comes down

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