Question

Select the correct answer. A ball is thrown straight down from the top of a building at a velocity of 16 ft/s. The building is 480 feet tall, and the acceleration due to gravity is 32 ft/s2. This problem can be represented using the following equation. How much time will the ball take to reach the ground

Answer 1

Answer:

The ball takes 5s to reach the ground

Explanation:

in order to solve this problem we use the kinematics equation with gravity as acceleration:

$h=v_0t+1/2*gt^2$

we replace the values

$0=1/2*32t^2+16t-480$

We solve this quadratic equation:

t=5s

t=-6s   (this solution has not physical sense)