18. a tennis ball is launched straight upward with an initial velocity of 24.5 m/s from the edge of a cliff that is 117.6 meters above the ground. which quadratic equation could be used to correctly determine when the ball will hit the ground:
4.9t2 + 24.5t + 117.6 = 0
-4.9t2 - 24.5t + 117.6 = 0
-4.9t2 + 24.5t - 117.6 = 0
4.9t2 + 24.5t - 117.6 = 0
-4.9t2 + 24.5t + 117.6 = 0
19. solve the equation you chose in question 18 to determine when the ball will hit the ground. (hint: if you don't get one of the answers listed for this question, then maybe you chose the wrong equation in #18. use this opportunity to double check your work! )
t = 8 seconds
t = 4 seconds
t = 3 seconds
t = -3 seconds
the ball will never reach the ground.
20. using the same equation, determine when the ball is at a height of 49 meters.