SOLUTION: a ball is thrown into the air its velocity is 45ft/s its height in freet after t sec is given by 45t-19t^2. Find the instaneous velocity when t=2

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Question 212724: a ball is thrown into the air its velocity is 45ft/s its height in freet after t sec is given by 45t-19t^2. Find the instaneous velocity when t=2
Found 2 solutions by drj, stanbon:
Answer by drj(1380) About Me  (Show Source):
You can put this solution on YOUR website!
A ball is thrown into the air its velocity is 45ft/s its height in feet after t sec is given by 45t-19t^2. Find the instantaneous velocity when t=2


Step 1. Let height = h = 45t-19t%5E2 where velocity is 45 ft/s

Step 2. Derivative of h = velocity = 45 - 36t.

Step 3. Substitute t=2 into Step 2. velocity = 45 -36(2)= 45 - 72 = -27 ft/s

Step 4. Since velocity is negative it is heading down at 27 ft/s.

I hope the above steps were helpful.

And good luck in your studies!

Respectfully,
Dr J

For free Step-By-Step Videos on Introduction to Algebra, please visit http://www.FreedomUniversity.TV/courses/IntroAlgebra.





Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
a ball is thrown into the air its velocity is 45ft/s its height in freet after t sec is given by 45t-19t^2. Find the instaneous velocity when t=2
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If you are studying calculus, evaluate the derivative at t = 2.
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If h(t) = -19t^2+45t
then h'(t) = -38t+45
and h'(2) = -38(2)+45 = -76+45 = -31
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Cheers,
Stan H.