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: Center of Mass with Cubes

  1. Apr 5, 2012 #1
    1. The problem statement, all variables and given/known data

    9) Three cubic boxes, each with side 0.1m, are stacked on top of one another. The lowest one is filled with gold bars and has mass 25kg; the middle one contains aluminum bars and has mass 10kg. The top one contains balsa wood and has mass 2kg. The height above the floor of the center of mass of the three boxes is _______.

    2. Relevant equations

    [itex]\Sigma[/itex]mx / [itex]\Sigma[/itex]m

    3. The attempt at a solution

    I put the origin at the bottom of the gold bar.

    (25 kg)(0.1m) + (10 kg)(0.2 m) + (2 kg)(0.3 m) / 37 kg = 0.137 m
  2. jcsd
  3. Apr 5, 2012 #2


    User Avatar
    Science Advisor
    Homework Helper

    Hi PeachBanana! :smile:
    Are these those special boxes with the centre of mass at the top? :wink:
  4. Apr 5, 2012 #3
    Oh. It looks like I forgot the rule about symmetrical objects having their CM's in the center.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook