help me with this

Question

A ball is dropped from a cliff that is 464 feet high. The height of the ball (in feet) after t seconds is given by the formula h(t) = 464 - 16t2. How many seconds (to the nearest tenth) will it take for the ball to hit the ground?



A. 21.2 sec
B. 5.4 sec
C. 13456 sec
D. 21.5 sec

Answer 1

Set h(t) = 0 and solve for t.

 

464 - 16t² = 0

 

t = √(464/16) sec = ? sec

 

Evaluate t.

Answer 2

16t^2 = 464

t^2 = 29

t = √29 = 5.4 s