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

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) (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 = 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) (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
------------------------------------------
If you are studying calculus, evaluate the derivative at t = 2.
---------------------
If h(t) = -19t^2+45t
then h'(t) = -38t+45
and h'(2) = -38(2)+45 = -76+45 = -31
========================================
Cheers,
Stan H.
RELATED QUESTIONS
A ball is thrown into the air with an initial upward velocity of 45 ft/s. Its height (h)... (answered by Alan3354)
A ball is thrown into the air with the in initial upward velocity of 45 ft/s. It's height (answered by Alan3354)
When a ball is thrown upward at a speed of 19 m/s, its height s above the ground (in... (answered by bucky,mathstutor494)
When a ball is thrown upward at a speed of 19m/s, its height s above the ground (in... (answered by Alan3354)
A ball is thrown into the air with an upward velocity of 36 ft/s. Its height h in feet... (answered by Alan3354)
A ball is thrown into the air with an upward velocity of 36 ft/s. Its height h in... (answered by solver91311)
A ball is thrown into the air with an upward velocity of 48ft/s it's high eight in feet (answered by stanbon)
A ball is thrown into the air with an upward velocity of 48ft/s it's high eight in feet (answered by Edwin McCravy)
I need help with a Calculus I question: If a ball is thrown into the air with a... (answered by htmentor)