Solving a Rocket Motion Problem

[drew1989]

Ok here's a question i had for homework, but i am having some trouble with it:

a rocket is fired from rest with an acceleration at=22.8m/s at an elevation angle of theta=62.4. the rocket travels in a straightline for 8.95 seconds, when the fuel runs out. at this time it becomes a projectile and falls back to the ground. fill in the tables

they ask for:

straightline

total horizontal vertical

vi vi vi
vf vf vf
d d d
a a a
t t t

and they ask for

projectile

up down horizontal


my answers were

total horizontal vertical

vi 0 vi 0 vi 0
v 204.06 vf 159.18 vf 147.18
d 913.17 d 809.25 d 423.07
a 22.8 a 20.2 a 10.6
t 8.95 t 7.9 t 4.2

i got these answers by using the pythagorean theorem and using the vf=vi+at formula. if these are right could you tell me, if not tell me what i was doing wrong. after i get to projectile it is easy but i think i made a mistake. would the time be the same for all?

 

[member 553083]

projectileup down horizontalvi 204.06 vi 147.18 vi 159.18vf 0 vf 0 vf 0d 423.07 d 913.17 d 809.25a -10.6 a -20.2 a 0t 4.2 t 7.9 t 7.9Yes, your answers for both tables are correct. The time for each motion would be the same because the rocket travels in a straight line for 8.95 seconds until it runs out of fuel and becomes a projectile.