Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Can you combine two accelerations together?

  1. Jul 17, 2015 #1
    When I was doing an exercise on projectile motion, there was a question that asked something like the max. altitude reached by an accelerating rocket. After some calculations, I got 23.96ms-2 as the vertical acceleration, then I minus it with 9.8ms-2 (gravitational acceleration as the two accelerations, I thought, should work against each other). Turns out, this is wrong and I should calculate the rest with 23.96ms-2 as the vertical acceleration. So my question is, why am I not supposed to minus 23.96 with 9.8? Because you can combine tangential acceleration and radial acceleration together to give a "resultant acceleration", but why is it not my case?

    Thanks!
     
  2. jcsd
  3. Jul 17, 2015 #2
    I think you'll have to post the original question to get a clear reply. All that comes to mind is that gravity had already, in some way, been accounted for.
     
  4. Jul 17, 2015 #3
    Question 65
    20150717_205325.jpg
     
  5. Jul 17, 2015 #4

    russ_watters

    User Avatar

    Staff: Mentor

    As Puma suggested, the acceleration given in the problem is the actual acceleration of the rocket, not the thrust of the engine.
     
  6. Jul 17, 2015 #5
    Thank you guys!
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook