(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A rocket is launched off and accelerates vertically up at 10 m/s^{2}. At 20 seconds, the motors are turned off, but the rocket keeps going up.

a) What height did it reach?

b) What was the time it needed to reach that height?

g: - 9.8 m/s^{2}

a: 10 m/s^{2}

final velocity: 0 m/s (Not sure).

t=20 s

2. Relevant equations

h= vo (t) + g(t)^{2}/2

t=(vf-vo)/g

vo= vf-g(t)

3. The attempt at a solution

I needed to find initial velocity to find height so I did.

vo=vf-g(t)

vo= 0 m/s - (-9.8m/s^{2})(20)

vo= 196 m/s

Now I just substituted to find height.

h= vo(t) + (g (t)^{2})/2

h= 196 m/s (20s) + (-9.8 m/s^{2}(20)^{ 2})/2

h=3920 m + -3920 m/

h= 3920 m - 1960 m

h= 1960 m

I really have no clue how do to even start the problem because I'm not sure what is the time total. I was thinking that after it stops accelerating, every second it decreases 1 m/s on it's acceleration so that would 10 more seconds to the total timing.

Any help would be appreciated it. Thanks.

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# Homework Help: A rocket is launched, it stops accelerating after a period of t but it keeps going up

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