SOLUTION: A rocks falls from a tower that is 320 ft high. As it is falling, it height is given by the formula h=320--16t^2. How many seconds (in tenths) will it take for the rock to hit th

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: A rocks falls from a tower that is 320 ft high. As it is falling, it height is given by the formula h=320--16t^2. How many seconds (in tenths) will it take for the rock to hit th      Log On


   

Question 976217: A rocks falls from a tower that is 320 ft high. As it is falling, it height is given by the formula h=320--16t^2. How many seconds (in tenths) will it take for the rock to hit the ground? h=0
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
h+=+320-16t%5E2


0+=+320-16t%5E2 Plug in h+=+0


16t%5E2+=+320 Add 16t%5E2 to both sides.


t%5E2+=+320%2F16 Divide both sides by 16.


t%5E2+=+20


t+=+sqrt%2820%29 Apply the square root to both sides


t+=+sqrt%284%2A5%29


t+=+sqrt%284%29%2Asqrt%285%29


t+=+2%2Asqrt%285%29


t+=+4.47213595499958 Use a calculator here


t+=+4.5 Round to the nearest tenth


-------------------------------------------------------


It will take approximately 4.5 seconds for the object to fall 320 ft. This is ignoring air resistance.


------------------------------------------------------------------------------------------------------------------------

If you need more one-on-one help, email me at jim_thompson5910@hotmail.com. You can ask me a few more questions for free, but afterwards, I would charge you ($2 a problem to have steps shown or $1 a problem for answer only).

Alternatively, please consider visiting my website: http://www.freewebs.com/jimthompson5910/home.html and making a donation. Any amount is greatly appreciated as it helps me a lot. This donation is to support free tutoring. Thank you.

Jim
------------------------------------------------------------------------------------------------------------------------