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Homework Statement
How much time does it take from the rocket gets shot up, till it reaches the ground again?
The rocket accelerates 30m/s^2 for the first 3 seconds, and accelerates downwards 6m/s^2 after.
Homework Equations
(vv0) / a = t to find time
The Attempt at a Solution
2ad=v^2v0^2
d= time
v=speed before landing
v0= starting speed 45m/s
I found v0 to be 45, (810/18)
810m the highest it gets, after 18 seconds.
i find v0^2 to be 2025
the distance must be 810 times 2? so 1620meter
I know the acceleration is 6 but ill just write 6 here for now
2*(6)*1620= 19440
2025+19440=21465
so v^2=21465
v=146
i go back to v=v0+at
(vv0) / a = t
(146  45) / 6 = 16
the answer is supposed to be 34sec, and im confused:)
my guess is i do something wrong with v or v0, i take v0 as the starting point (at 18 sec)
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