Problema Solution

If an object is thrown upward with an initial velocity of 192ft/seconds, then its height after t seconds is given by the following equation.

h=192t-32t^2

a. Find the maximum height attainted by the object.

b. Find the number of seconds it takes the object to hit the ground.

Answer provided by our tutors

h=192t-32t^2


192 ft/s the initial velocity


h = the height


t = the time in seconds


a. Find the maximum height attainted by the object


We need to find the maximum of the parabolic function:


h=-32t^2 + 192t


The quotient in front of t^2 is -32<0 follows the function has maximum equal to:


h max = c - b^2/(4a), where a = -32, b = 192, c = 0


h max = 0 - 192^2/(4*(-32))


h max = 288 ft


b. Find the number of seconds it takes the object to hit the ground.


The object hits the ground when h = 0 for some t > 0 that is:


-32t^2 + 192t = 0

........


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........

t = 6 s


It takes 6 seconds for the object to hit the ground.