A water rocket is projected vertically upward from the ground. Its a height(h) m above the ground after t seconds is given by h=
1 answer:
Answer:
after 4 seconds
Step-by-step explanation:
Given
h = 20 - 5(t - 2)²
When rocket is on ground then h = 0
Equate to zero and solve for t
20 - 5(t - 2)² = 0 ( subtract 20 from both sides )
- 5(t - 2)² = - 20 ( divide both sides by - 5 )
(t - 2)² = 4 ( take the square root of both sides )
t - 2 = ± = ± 2 ( add 2 to both sides )
t = 2 ± 2
Thus
t = 2 - 2 = 0 ← when rocket is launched
t = 2 + 2 = 4 ← when rocket hits the ground
The rocket reaches the ground after 4 seconds
You might be interested in