High school maths

Question

Suppose a flare is launched from a life raft with an initial upward velocity of 192 feet per second. The expression -16t^2 +192t gives the height, in feet, of the flare t seconds after it was launched up into the air. How high will the flare reach? 

 

a.
576 feet

b.
320 feet

c.
560 feet

d.
432 feet

 

Answer 1

For the function f(x) = ax² + bx + c, the maximum (or minimum) occurs at -b/2a. (No Calculus needed!)

For the given function that is -192/(2)(-16), or 6.

 

f(6) = -16(6)² + 192(6)

 

Can you calculate f(6)?

Answer 2

See the answer to your previous question. Following the same steps will get you the answer.

 

Are you currently in calculus? You can take the derivative of the function -> 0=-32*t+192, and then solve for t. This gives you the time value when the ball is at the maximum height. Plug that number back into the original equation to find the answer.