If the ball hit the ground it means that its height is equal to 0. In order to find the time after the ball <span>will hit the ground, we need to find the solution of the equation h(x)=0 which is different to 0.
-4.9x^2+21.3x=0
x(-4.9x+21.3)=0
-4.9x+21.3=0
x=21.3/4.9 = 4.3469 seconds</span>
S(t) = 3.82 - 0.2t
Step-by-step explanation:
After 7 weeks, the ice is 2.42 meters thick. The ice loses 0.2 meters of thickness per week; this means on the 7th week, it has lost 7(0.2) = 1.4 meters of thickness.
This means the ice started at 2.42+1.4 = 3.82 meters thick.
Our function will start at the original thickness of the ice, 3.82 meters.
Since the ice is losing thickness, we will subtract; it loses at a rate of 0.2 meters per week (t), which gives us 0.2t. This is subtracted from the original, 3.82 meters, giving us
S(t) = 3.82 - 0.2t
