?: A rocket is fired up at 5 m/s^2. After a certain time, the engine fails and the rocket goes into freefall. It hits the ground 12 seconds after engine failing. Find V(final) and height that the rocket reaches.(adsbygoogle = window.adsbygoogle || []).push({});

the the way down...

Vf = Vi - at

set Vf = 0 b/c when it hits the ground, V = 0

Vi = 9.8(12)

Vi = 117.6 m/s

so plugging this back into the trip up...

Vf = Vi - at

Vf = 117.6 m/s

Vi = 0 b/c it starts at 0 before fired.

117.6 m/s = - (5 m/s^2)t

t = 23.52 sec

i hope this is right so far... so how do i find V(final) and the height using this? the rocket doesn't stop when the engine dies. it continues up for a little bit before starting the freefall...

thx guys.

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# Homework Help: 2d Kinematics: rocket fired up, engine dies

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