Answer:
Step-by-step explanation:
Given
Required:
Determine the time taken to return to the ground
From the equation given; height (h) is a function of time (t)
When the rocket returns to the ground level, h(t) = 0
Substitute 0 for h(t) in the given equation
becomes
Solve for t in the above equation
Factorize the above expression
Split the expression to 2
Solving the first expression
Divide both sides by -4
Solving the second expression
Add 30 to both sides
Divide both sides by 4
Hence, the values of t are:
and
shows the time before the launching the rocket
while
shows the time after the rocket returns to the floor