Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

Topic: Easy problem but my solution isn't right
Replies: 5   Last Post: Sep 5, 2006 4:45 PM

 Messages: [ Previous | Next ]
 Jason Fahy Posts: 15 From: Edmonton, AB Registered: 9/5/06
Re: Easy problem but my solution isn't right
Posted: Sep 5, 2006 4:45 PM

An object is thrown upward. The height, h, is in feet. The time, t, is in second. The Formula is given by the equation: H=-16T^2+96T Determine the time, if the object reach a height of 50.

50 = -16T^2 + 96T

16T^2 - 96T + 50 = 0

8T^2 - 48T + 25 = 0

Doing the quadratic formula, I get...

T = [48 +/- sqrt(2304-800)]/16

T = [48 +/- 38.8]/16

T = 0.575 sec (on the way up) or
T = 5.425 sec (on the way down).

In other words, I'm getting the same thing you are. Not sure where the problem is...

Date Subject Author
8/22/06 Kai
8/23/06 Memtonen
8/24/06 G.E. Ivey