1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Thrust separate from acceleration?

  1. Jan 22, 2013 #1
    1. The problem statement, all variables and given/known data
    A model rocket blasts off vertically from rest at time t=0 being pushed by an engine that produces a constant thrust force F up. The engine blasts away for t seconds and then stops. Find the height y and vertical velocity that the rocket has reached by the end of the blast time t.

    2. Relevant equations

    3. The attempt at a solution
    a = F
    y(t) = .5Ft^2

    Is acceleration really the same as the thrust, or is acceleration the thrust - the effect of gravity?
  2. jcsd
  3. Jan 22, 2013 #2


    User Avatar
    Science Advisor
    Homework Helper

    Thrust is the force pushing the rocket up. mg is the gravitational force pulling the rocket down. Both forces are acting on the rocket while the engine is on. The 'F' in F=ma is the total force. So no, F is not the same as acceleration. You'll need to express the answer in terms of the mass 'm' of the rocket.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook