Suppose a ball was dropped from a TV tower 2120 feet high. The time it takes an object to free-fall from the top of this tower to the ground can be represented by the equation s = −16t2 + 2120, where s is the distance from the ground in feet and t is the time in seconds. Approximately how long would it take the object to reach the ground? Round your answer to the nearest tenth.

My answer:
If a ball is dropped from 2120 feet, it will take approximately 132.5 seconds to reach the ground.

1 answer

s equals zero on the ground

0 = −16t2 + 2120

16t2 = 2120 ... t^2 = 132.5 ... this is the SQUARE of the time

take the square root to find the fall time