Answer:
70 seconds
Step-by-step explanation:
Given that;
The initial velocity of the bullet fired = 1120 ft/s
Initial height h = 8 feet
The expression to determine how many seconds it takes the bullet to hit the ground is:
Thus;
Replacing the value of = 1120 and h = 0 (i.e. when h =0) in the above expression; we have:
= -16t² + 1120t + 8
mulitiply through by (-)
= 16t² -1120t - 8
Divide through by 8
= 2t² - 140t - 1
The above expression forms a quadratic equation.
where;
a = 2
b = -140
c = - 1
So, by using the quadratic formula , we have:
= 70
Thus, the time (in seconds) it took the bullet to it the ground = 70 seconds