Frank kicks a soccer ball off the ground and in the air with an initial velocity of 30 feet per second. Using the formula H(t) = −16t2 + vt + s, what is the maximum height the soccer ball reaches?

Question

anonymous · Answer

a. 14.1 feet 	
	b. 13.7 feet 	
	c. 13.2 feet 	
	d. 15.2 feet

phi · Answer

they tell you "Frank kicks a soccer ball off the ground "   which means s in the equation is 0 
the way you know this, is to say,  at time  t=0 (at the start)   H(0)= -16*0*0+ v*0 + s 
or H(0)= s 
if the ball is on the ground at the start, its height is 0,  os H(0)=0 =  s

they tell you "initial velocity of 30 feet per second. "  that means v=30

your equation is
H(t) = -16 t^2 + 30 t

that is a parabola.  You need to find the vertex (highest point) of this vertex

anonymous · Answer

Oh okay. Thanks!

phi · Answer

see http://hotmath.com/hotmath_help/topics/vertex-of-a-parabola.html for how to find the t value of the vertex. use that t value to find the height

anonymous · Answer

Got it!!! :) thanks<3