A tennis ball is launched with an initial velocity of 24.5 m/s from the edge of a cliff that is 117.6 meters above the ground. Which quadratic equation could be used to correctly determine when the ball will hit the ground:
4.9t2 + 24.5t + 117.6 = 0
-4.9t2 - 24.5t + 117.6 = 0
-4.9t2 + 24.5t - 117.6 = 0
4.9t2 + 24.5t - 117.6 = 0
-4.9t2 + 24.5t + 117.6 = 0
could you please explain how u got your answer?
2007-10-22 10:45:37 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
I agree with Iron Duke. Here is a little more as to why.
Height of an object is measured with the following equation.
H(t)=-g/2(t)^2+vo(t)+ho
This sounds complicated but H(t) simply means a function for height based on time.
-g/2 means the force of gravity over -2. Since the force of gravity (on earth) is 9.8
then this number is always -4.9
Vo means initial velocity. Which in your problem was given as 24.5 (velocity will be positive for any thrown or fired object sent up into the air).
ho means initial height or beginning height.
In your problem this was given as 117.6
Plugging in the given values:
Equation H(t)=-g/2(t)^2+vo(t)+ho
becomes:
H(t)=-4.9(t)^2+24.5t+117.6
2007-10-22 11:01:27 · answer #1 · answered by Shaun B 3 · 0⤊ 0⤋
-4.9t2 + 24.5t + 117.6 = 0
It has to have a negative t^2 term in order to have a maximum value. It has to have +117. 6 because that is the positive height the ball was launched from. It has to be +24.5t because the initial velocity was positive. Answer is the only answer that meets these criteria.
2007-10-22 10:54:33 · answer #2 · answered by ironduke8159 7 · 0⤊ 0⤋
-4.9t2+24.5t+117.6=0
2007-10-22 11:18:52 · answer #3 · answered by valenciahf 1 · 0⤊ 0⤋