Aprojectile is thrown upward so that its distance above the ground after t seconds is h = -16t^2 440t. after how many seconds does it reach its maximum height?

When the projectile reaches
its maximum height, the slope of the projectile is horizontal at that maximum point, hence its derivative is zero.

Given



The derivative is given by:


At maximum height,





Now let us solve for t, to obtain;

44 % of 325 is 143