David S.

asked • 11/05/17

How can I figure this problem out?

So my problem on my precalculus homework is “Rodney shoots a basket at 6.5ft above the ground. It’s initial velocity is 25 feet per second. How many seconds after shooting does the ball go through the hoop?”
 
im so confused

Arturo O.

We need to know the height of the hoop, which the problem statement does not provide.  Suppose it is H (in feet).  Assuming the ball is tossed vertically up (another detail that is missing from the problem statement), the height h as a function of time t is
 
h(t) = (-1/2)32t2 + 25t + 6.5 = -16t2 + 25t + 6.5
 
h in feet, t in seconds
 
When it reaches a height H,
 
H = -16t2 + 25t + 6.5
 
-16t2 + 25t + (6.5 - H) = 0
 
Solve this quadratic equation for t.  I should give a negative and a positive solution,  Since t starts at t = 0, the answer is the positive solution.  Plug in the correct value of H and solve.
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11/05/17

1 Expert Answer

By:

Arturo O. answered • 11/05/17

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