rocket acceleration questions (1 Viewer)

[Fermentation]

Could somebody help me with these questions or show the formulas needed to do them... either would be good,

A rocket has a mass of 400kg, 75% being fuel. It develops a thrust of 8000N
a) calculate its initial acceleration.
b) calculate its acceleration when half its fuel has been consumed

the answers should be 10.2ms-2 and 22.2ms-2

 

[EmeraldTempest]

Hi!
I am having the same problem with the same question (on page 14 of the physics dot point book. how is it done?

 

[Slowness]

F = MA
8000 = 400 A
A = 8000/400
A = 20 - 9.8 (gravity).
= 10.2 ms^-2



400X.75 = 300
300/2 = 150
100+150 = 250

F = MA
A = 8000/250
A = 32 -9.8 (gravity)
= 22.2 ms^-2



Thanks to a friend that helped as well

 

[iRuler]

Hi!
I am having the same problem with the same question (on page 14 of the physics dot point book. how is it done?

how in the world did you end up digging a thread 3 years old

 

[EmeraldTempest]

how in the world did you end up digging a thread 3 years old

haha - did a search to see if someone had asked the same question before and found that they had.

cheers for the answer

planning to drop physics now that the half yearly is over.