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Finding initial velocity given max height and distance only

  • Thread starter dane811
  • Start date
1. The problem statement, all variables and given/known data

A golfer hits a ball, giving it a maximum height of 20 m. If the ball lands 130 m away at the level from which he hit it, what was its initial velocity? (Neglect air resistance)

2. Relevant equations

3. The attempt at a solution

I found the angle to be 31.6, so I tried vi cos 31.6 = 130 /(1/2)((-vi sin 31.6)/-9.81), but I'm not seeing how to solve for initial velocity. There has to be an easier way to do this, and I'm convinced I'm making it more complicated than it really is!

Any help would be appreciated!
How do you get the angle to be 31.6°?

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