Calculating Exhaust Gas Speed for a 4200kg Rocket Launch

[pbumper1]

Homework Statement

A 4200kg rocket is to be accelerated at 4.0g at take-off from the Earth.
If the gases can be ejected at a rate of 28 kg/s, what must be their exhaust speed?

Homework Equations

Fthrust=mv2-mv1/t2-t1

The Attempt at a Solution

Multiplied 4200kgx4x9.8/28kg/s=-5900

 

[G01]

Your work seems fine to me. Do you have any specific questions on this problem?

 

[pbumper1]

The answer is wrong and don't understand why it is?

 

[pbumper1]

I figured it out for future reference, since the rocket has to overcome 1g you add it to the 4g. You use the same equation. 4200x5x9.8/28=7400m/s

 

[G01]

I figured it out for future reference, since the rocket has to overcome 1g you add it to the 4g. You use the same equation. 4200x5x9.8/28=7400m/s

Good catch! Nice job.