SOLUTION: I believe this is supposed to be solved by using the quadratic equation, but I'm not sure how to work it. Any help would be very much appreciated!! If a pebble is dropped towar

Algebra.Com
Question 49912This question is from textbook Beginning Algebra
: I believe this is supposed to be solved by using the quadratic equation, but I'm not sure how to work it. Any help would be very much appreciated!!
If a pebble is dropped toward a pond from the top of a 240-ft building, its height h after t s is given by h = 16t^2 + 240. How long does it take the pebble to pass through a height of 120 ft? This question is from textbook Beginning Algebra

Answer by AnlytcPhil(1806)   (Show Source): You can put this solution on YOUR website!

I believe this is supposed to be solved by using the quadratic equation,
but I'm not sure how to work it. Any help would be very much 
appreciated!! If a pebble is dropped toward a pond from the top of a 
240-ft building, its height h after t s is given by h = 16t^2 + 240. How 
long does it take the pebble to pass through a height of 120 ft?

That formula is wrong. It should be h = -16t² + 240.  

Just plug 150 for h in the equation and solve first for t². Then take
square roots of both sides.  You'll get approximately t = 2.7 seconds.

Edwin
RELATED QUESTIONS

WHat is the graph for this equation? f(x)= x^2+6x+8 I'm not sure if the quadratic (answered by Fombitz)
-3sqrt5x^3 * sqrt10x^3 I'm not too sure how this would be solved so any help would be... (answered by harpazo)
Is -4x squared = 0 a quadratic equation? I am supposed to solve each quadratic equation... (answered by stanbon)
The radical √(85+√2736) can be expressed as √a + √b, where a < b. What is the... (answered by ikleyn,math_tutor2020)
I tried doing the first part of this problem, but not sure if it is right. I dont know... (answered by stanbon)
Factor and check by multiplying x^8 + 3x^7 just Factor: 81c^6 - 3d^6 Are... (answered by richwmiller)
I am not sure what this is called but could you show me how to work it out step by step?... (answered by wuwei96815,celeste)
Hello. I am stumped on a homework assignment. I have to solve a quadratic equation using... (answered by Alan3354,ewatrrr)
This question deals with solving the quadratic equation by using the quadratic formula.... (answered by scott8148)