posted by Anonymous .
A ball is thrown from an initial height of 2 meters with an initial upward velocity of 25m/s. The ball's height h (in meters) after t seconds is given by the following.
Find all values of t for which the ball's height is 12 meters.
Round your answer(s) to the nearest hundredth.
h(t) = 2+25t-4.9t^2
2+25t-4.9t^2 = 12
t= 0.44 and 4.66 seconds
To find when the ball's height is
meters, we substitute
and solve for
In order to solve for
, we first rewrite the equation in the form
Next, we use the quadratic formula to solve for
Our equation has
We use these values in the formula.
We get that
can be either of two values to solve the equation.
Rounding these values to the nearest hundredth, we get
So, the ball's height is
meters at approximately
seconds (on its way up) or
seconds (on its way down).