Pierre hit a baseball, and the flight of the ball was modeled by the following equation: h = -16t2 + 61t + 3. After how many seconds will the ball fall to the ground, if it is not caught? Round your answer to the nearest tenth.

(a) 4.0 seconds

(b) 3.8 seconds

(c) 3.7 seconds

(d) 3.9 seconds

Question

Pierre hit a baseball, and the flight of the ball was modeled by the following equation: h = -16t2 + 61t + 3. After how many seconds will the ball fall to the ground, if it is not caught? Round your answer to the nearest tenth.

		
(a) 4.0 seconds
		
(b) 3.8 seconds
		
(c) 3.7 seconds
		
(d) 3.9 seconds

campbell_st · Answer

you need to find when h = 0 ( the ball is on the ground)

then 

$$0 = -16t^2 + 61t + 3$$

use the general quadratic formula to find t

$$t = \frac{-61 \pm \sqrt{61^2 - 4\times -16\times3}}{2\times-16}$$

only consider the positive t value in your solution.

anonymous · Answer

When the height is zero...