PHYSICAL SCIENCE: Mr. Alim's science class launched a toy rocket from ground level with an initial upward velocity of 60 feet per second. The height h of the rocket in feet above the ground after t seconds is modeled by the equation h = 60t - 16t^2. How long was the rocket in the air before it returned to the ground? h=60t - 16t^2
0=60t-16t^2 now moved the factors to the right of the zero to the left side of the zero like this -16t^2+60t=0
now factor -16t^2 + 60t = 0
-4t (4t-15t)=0
divide the equation by 4 and it will get:
t(4t-15)
now take each term and equal to zero:
t=0
4t-15=0
now add 15 to each side: 4t-15+15=o 0+15
you get: 4t=15
now divide by 4
answer is t=15/4 = 3.75 seconds
The rocket was on the air 3.75 seconds before returning to the ground.