The equation y=-4.9t^2+42t+18.9 describes the height (in meters) of a ball tossed up in the air at 42 meters per second from a height of 18.9 meters from the ground, as a function of time in seconds. In how many seconds will the ball hit the ground?
+129899 y= -4.9t^2+42t+18.9
The object will hit the ground when y = 0
Use the quadratic formula to find when y = 0
-42 ±√ [ 42^2 - 4(-4.9)(18.9) ] -42 ± √[2134.44]
________________________ = ______________ =
2(-4.9) -9.8
-3/7 sec (reject) or 9 sec (accept)
+2864 Lol! My math teacher made this the last question on our algebra quiz last year! Brings back good memories of day dreaming in math class!
