A tennis ball machine serves a ball vertically into the air from a height of 2 feet, with an initial speed of 120 feet per second. What is the maximum height, in feet, the ball will attain?

Round to the nearest whole foot.

pleez help I'm lost.. ):

Question

A tennis ball machine serves a ball vertically into the air from a height of 2 feet, with an initial speed of 120 feet per second. What is the maximum height, in feet, the ball will attain?

Round to the nearest whole foot. 

pleez help I'm lost.. ):

anonymous · Answer

yeah i bet since no one serves a tennis ball straight up

anonymous · Answer

you are trying to find the maximum of $$-16t^2+120t+2$$ which is at the vertex q

anonymous · Answer

first coordinate of the vertex of $y=ax^2+bx+c$ is always $-\frac{b}{2a}$ which in your case is 
$$-\frac{120}{2\times (-16)}$$ or 
$$3.75$$

anonymous · Answer

so 3.75 is my final answer

anonymous · Answer

?

anonymous · Answer

second coordinate is what you get when you replace $t$ by $3.75$ in 
$$-16t^2+120t+2$$

anonymous · Answer

oh

anonymous · Answer

use a calculator q

anonymous · Answer

or use this http://www.wolframalpha.com/input/?i=-16%283.75%29^2%2B120*3.75%2B2

anonymous · Answer

thank u rue the best eve :D

anonymous · Answer

lol *you are*

irishboy123 · Answer

the third of the common equations used to model Newtons laws of motion will give a direct answer. ie $$v^2 = u^2 + 2ax$$ all three should stick in the memory very easily. http://www.bbc.co.uk/bitesize/higher/physics/mech_matt/analyse_motion/revision/2/