1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Questions dealing with force

  1. Sep 14, 2005 #1
    A couple of questions in this problem.

    A 20,000kg rocket has a rocket motor that generates [tex]3.0 *10^5N[/tex] of thrust.

    1. What is the rocket's initial upward acceleration?

    I used the formula F=MA and got 15 but apparently thats not the right answer. So Im stumped.

    2. At an altitude of 5000m the rocket's acceleration has increased to 6.0m/s^2. What mass of fuel has it burned?

    Im assuming I need the answer to the first part and that the 5000m is irrelevant.

    [tex]300000=m_1*6[/tex] Then I should be able to get the answer [tex]20000-m_1[/tex]

  2. jcsd
  3. Sep 15, 2005 #2
    I think you are on the right track. With problems like these the first step is to draw a free body diagram then sum the forces - perhaps the problem states that the rocket is taking off from Earth? After summing the forces you should have the answer for the Total a. Let me know if that helps.

  4. Sep 15, 2005 #3
    Ah ok I see why my answer is wrong. I needed to subtract weight from the thrust.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?

Similar Discussions: Questions dealing with force