Re: polynomial Inequalities

I don't understand why you titled this thread "polynomial inequalities." From the data you have been given you have $\displaystyle s=0m,\ v_o=0 m/s, \ s_0=2000m$. So the formula becomes:

$\displaystyle 0m = -\frac 1 2 (3.92\frac m {s^2} ) t^2 + 0t +1000m$

Rearrange and solve for t.

Re: polynomial Inequalities

because thats what it is :/

Re: polynomial Inequalities

Ok if i solve this using the quadratic formula it is unsolvable

Re: polynomial Inequalities

Quote:

Originally Posted by

**darkangel06** Ok if i solve this using the quadratic formula it is unsolvable

This is simpler than you think, and it's not an inequality:

$\displaystyle 0 = - \frac 1 2 (3.92 \frac m {s^2})t^2 +1000$

$\displaystyle \frac 1 2 (3.92 \frac m {s^2})t^2 = 1000$

$\displaystyle t^2 = \frac { 1000 m} {\frac 1 2 (3.92 \frac m {s^2})}$

$\displaystyle t = \sqrt {\frac {2 (1000m)}{3.92 \frac m {s^2}}} $

You can use the quadratic formula if you want to find the roots of $\displaystyle at^2 +bt+c = 0$, where $\displaystyle a= - \frac 1 2 (3.92), \ b=0,\ c = 1000$. Don't forget that minus sign in the 'a' coefficient!

Re: polynomial Inequalities

Re: polynomial Inequalities

Quote:

Originally Posted by

**darkangel06** well g= -3.92 not +3.92

if a is acceleration, you would write s = at^2

if the acceleration is negatinve, as in the gravity, a = -3.92.

do you see the negative sign in ebaines post.