Answer:
He will take 1.5 seconds to hit the water
Explanation:
* The formula h(t) = -16t² + vt + s
- h is the his height above the water
- v is his initial up-word velocity
- s is his starting height
- t is the time
* When he hits the water h(t) = 0
- because h is his height above the water
∴ -16t² + vt + s = 0
∵ v = 8 ft/s
∵ s = 24 ft
∴ -16t² + 8t + 24 = 0 ⇒ × (-1)
∴ 16t² - 8t - 24 = 0 ⇒ ÷ 8
∴ 2t² - t - 3 = 0 ⇒ by using factorization
∴ (2t - 3)(t + 1) = 0
∴ 2t - 3 = 0 ⇒ 2t = 3 ⇒ t = 3/2 = 1.5 sec
∴ t + 1 = 0 ⇒ t = -1 ⇒ rejected the time is positive value
* He will take 1.5 seconds to hit the water