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Force Problem (Rocket Launch)

  • Thread starter cheerspens
  • Start date
  • #1
92
0

Homework Statement


A Saturn-Apollo rocket has a mass of 5.40 x 105kg. What is the initial acceleration of the rocket if the thrust at lift off is 7.40 x 106 N?
How high will the rocket rise one minute after launch?

Homework Equations


Fg=mg
FNET=ma


The Attempt at a Solution


I used Fg=mg, plugging in 5.5 x 105 for m and 9.8 for g to get Fg=5.292 x 106 N.
I then used the FNET equation as so:
7.4 x 106-5.292 x 106=(5.4 x 105)(a)
And my answer was an acceleration of 3.89m/s2.
For the second question I got that the rocket would reach 233.4m one minute after launch.
Is this correct or how is this done correctly? Thanks!

Homework Statement





Homework Equations





The Attempt at a Solution

 

Answers and Replies

  • #2
rock.freak667
Homework Helper
6,230
31
Your method is correct, but you did the operations wrong I believe. The thrust after lift off is the resultant force. So you need to add that to the weight and then get the acceleration.
 

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