- #1

clope023

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**[SOLVED] 2D motion**

A shell is fired with a horizontal velocity in the positive x direction from the top of an 80 m high cliff. The shell strikes the ground 1330 m from the base of the cliff.

http://courses.science.fau.edu/~rjordan/quizzes/phy2043/images/3.07.gif

I think relevant equations would be x = (v0cosα0)t

y = (v0sinα0)t-1/2gt^2

vx = v0cosα0

vy = v0sinα0-gt

R = v0^2(2sinα0)/g

I think α0 = 90 degrees?

I used 1330m = v0^2(2sin90)/9.8, got v0 = 80.6m/s, one of the answer choices was 82m/s but it was wrong; the answer turned out to be 330m/s; I don't know how they do it with the info presented, any help is appreciated.

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