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: Pencil in elevator

  1. Sep 24, 2009 #1
    A pencil is dropped from inside an elevator moving 5m/s upward. Calulate the time it takes to drop from 1m to elevator floor and its velocity.

    I approached as a velosy problem. Is this more of a Force problem ? I could calculate the velocity and time it took while the elevator was at a standstill, but got stuck when its in motion. Can someone please guide me in the right direction? THanks!
  2. jcsd
  3. Sep 26, 2009 #2


    User Avatar
    Homework Helper

    maybe show some working so we can see where you went wrong

    note the pencil will initially be moving up at 5m/s the same speed as the elevator & have a think about equivalence of inertial reference frames
  4. Sep 27, 2009 #3
    The concept you should apply is Galilean relativity; the laws of physics are the same in all inertial frames.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook