



 
Hi Dillon. The standard equations of projectile motion are
(Sometimes it is written as + ½ instead of  ½, but then you need to ensure g is a negative number). Where:
So in your question, y_{0} is 5 ft, v_{0} is 60 ft/sec, θ is 90°. So this equation simplifies to:
(Remember that sin 90° is 1, so that whole term can be removed). 1. How long is the ball in the air? That would be the value of t for which the height is 0 ft above the ground.
2. When is the ball at its maximum height? Notice that this equation is a parabola. That means that if y is the vertical axis and t is the horizontal axis, that we have a parabola opening downwards. The question asks, where is the vertex of this parabola? What is the horizontal (y) value at that point? If you put the equation into standard form for a parabola, you can easily read off the vertex. 3. What is the maximum height of the ball? You pretty much already solved this if you finished question 2. This is just the vertical coordinate of the vertex. Hope this helps,  


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