Problema Solution

A ball is thrown from an initial height of 6 feet with an initial upward velocity of 40ft/s . The ball's height h(in feet) after t seconds is given by the following.

h=6+40t-16t^2

Find all values of t for which the ball's height is 28feet.

Round your answer(s) to the nearest hundredth.

(If there is more than one answer, use the "or" button.)

Answer provided by our tutors

From the question:

h(0)=6 ft

v(0)=40 ft/sec

 

h(t)=6+40t-16t2

for h=28 ft

28=6+40t-16t2

or 16t2-40t+22=0

or 8t2-20t+11=0

on solvong the quadratic eqn

t=0.817sec and 1.683sec