Quadratic equation

Question

A ball is thrown from an initial height of 2 m with an initial upward velocity of 7M/S. The balls height H (in meters) after t seconds is given by the following h=2+7t-5^2 find all values of t for which the balls height is 3 meters

Answer 1

h=3=2+7t-5t^2

find all times t when height h = 3

initial height =2 meters, initial velocity = 7 meters per second

-5t^2 is really -4.9t^2 which is the force of gravity acting downward

since the problem rounded 4.9 off to nearest integer, the answer probably should be similarly rounded

5t^2 - 7t +1 = 0

t = 7/10 +/-(1/10)sqr(29)

= about 1.2385 and 0.11615 seconds,

= about 1 and 0 seconds