[SOLVED] got 5 problems i could use some help with

1. An open box is to be constructed from a square sheet of plastic by removing a square of side 2 inches from each corner, and then turning up the sides. if the box must have a volume of 242 cubic inches, find the length of one side of the open box

2.A ball is thrown vertically upward from the top of a building 112ft tall with an initial velocity of 96 feet per sec. the distance s (in feet) of the ball from the ground after t seconds is s=112+96t-16t^2.

After how many seconds will the ball pass the top of the building on its way down?

3. A projectile is fired from a cliff 400ft above the water at an inclination of 45degrees to the horizontal, with a muzzle velocity of 320 feet per second. the height h of the projectile above the water is given by

h(x)=-32x^2/(320)^2+x+400, where x is the horizontal distance of the projectile from the base of the cliff. how far from the base of the cliff is the height of the projectile a maximum?

4.Consider the quadratic model h(t)=-16t^2+40t+50 for the height (in feet), h of an object t seconds after the object has been projected straight up into the air. find the maximum height attained by the object. How much time does it take to fall back to the ground? Assume that it takes the same time for going up and coming down.

5.A flare fired from the bottom of a gorge is visible when the lare is above the rim. If it is fired with an initial velocity of 176ft/sec, and the gorge is 480 ft deep, during what interval can the flare be seen? (h=-16t^2+vot+ho)

the o's in the above formula are subscripts.

Im sure 3 of the five all use the same formula because i can see their working is very similar as well as their functions. A little help please.