Problema Solution
A ball is thrown directly up in the air from a height of 5.5 feet with an initial velocity of 65.5 ft/s. Ignoring air resistance, how long until the ball hits the ground? Use the formula h=-16t^2+65.5t+5.5, where h is the height of the ball in feet and t is the time in seconds after it is thrown. Round your answer to the nearest hundredth.
Answer provided by our tutors
the formula for the height of the ball in ft is
h(t) =-16t^2+65.5t+5.5, t is the time in seconds after it is thrown and t>0
click here to see the graph of this parabola and notice that we need to find the x-intercept of the parabola
that is the value of t for which h(t) = 0
-16t^2+65.5t+5.5 = 0
by solving the quadratic equation we find
t = 4.18 seconds rounded to the nearest hundredth
click here to see the step by step solution of the quadratic equations
after 4.18 seconds the ball will hit the ground.