Solve the problem.
-A ball is thrown downward with an initial velocity of 21 meters per second from a cliff that is 130 meters high. The height of the ball is given by the quadratic equationn $h = - 4.9 t ^ { 2 } - 21 t + 130$ 130 where h is in meters and t is the Time in seconds since the ball was thrown. Find the time it takes the ball to hit the ground. Round your answer To the nearest tenth of a second.
A)3.5 seconds
B)4.4 seconds
C)3.3 seconds
D)3.4 seconds

Question

Quizplus · Accepted Answer

To find the time it takes for the ball to hit the ground, we set $h = 0$ and solve the quadratic equation $-4.9t^2 - 21t + 130 = 0$. Using the quadratic formula or a calculator, we find that $t \approx 3.4$ seconds is the positive root of the equation, which represents the time it takes for the ball to reach the ground.

Solve the Problem h=−4.9t2−21t+130h = - 4.9 t ^ { 2 } - 21 t + 130h=−4.9t2−21t+130

Solve the Problem $h = - 4.9 t ^ { 2 } - 21 t + 130$