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!

Calculating Superman's Average Force! (due in 4 days!)

  1. Feb 8, 2013 #1
    1. The problem statement, all variables and given/known data

    Superman (m = 90 kg) jumps over a 78 m tall building by first accelerating from rest to his maximum velocity in 0.004 s. Subsequent to this time, Superman follows normal projectile motion. What is the average force acting on Superman that gives his upward acceleration?. In determining the initial velocity, ignore the distance superman travels during his initial acceleration stage. Also, assume he is jumping straight up. Do not use exponential notation in submitting your answer.

    2. Relevant equations
    The equations that I have gathered are:
    F=ma
    A=v/t
    vf^2=vi^2-2ad
    vf=vi+at


    3. The attempt at a solution

    I know that I have to find the Initial velocity first, but in order to do so I need either Time or Acceleration, which I have neither of. All I have found is that the downward force on superman due to gravity at any given time is 882.9N.

    Please guide me in the direction to get the answer! Also please dont just give me the answer as I need to learn how to do this for my Physics class!

    Thanks!
     
  2. jcsd
  3. Feb 8, 2013 #2

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    But you do know the initial velocity:
    ... you nee ##\sum F = ma##
     
  4. Feb 8, 2013 #3
    Duh! I dont know why I didnt realize that before. I also believe i've found vf

    I used vf^2=vi^2-2ad and got 39.099 m/s for the vf. If that is correct would i just use a=v/t to find out a?
     
  5. Feb 8, 2013 #4
    I got the answer. after i found vf i used a=v/t and then just used F=ma and my answer was 879727.5N

    Thank you for your help!
     
  6. Feb 8, 2013 #5

    Simon Bridge

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    No worries :)
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Calculating Superman's Average Force! (due in 4 days!)
Loading...