SOLUTION: use the height as a function of time in motion equation: h(t) = -16t squared + vt + c A baseball player hits a pitched ball when it is 4 ft above ground. The initial upward

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Question 587211: use the height as a function of time in motion equation: h(t) = -16t squared + vt + c A baseball player hits a pitched ball when it is 4 ft above ground. The initial upward velocity is 80 ft/sec. How long will it take for the ball to hit the ground?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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use the height as a function of time in motion equation: h(t) = -16t squared + vt + c A baseball player hits a pitched ball when it is 4 ft above ground.
The initial upward velocity is 80 ft/sec. How long will it take for the ball to hit the ground?
:
h(t) = -16t^2 + vt + c
from the information given we know
v = 80
c = 4
:
h(t) = -16t^2 + 80t + 4
When the ball hits the ground we have h(t) = 0, therefore:
-16t^2 + 80t + 4 = 0
simplify divide by -4
4t^2 - 20t - 1 = 0
Use the quadratic formula to find t
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x = t; b=-20, c=-1
t+=+%2820+%2B-+sqrt%28-20%5E2+-+4%2A4%2A-1+%29%29%2F%282%2A4%29+
Do the math, the positive solution
t = 5.0495 seconds
:
You should check this in the original problem