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: Urgent: Qns on motion and work !

  1. May 18, 2006 #1
    A man of mass "m" on an initially stationary boat gets off the boat by jumping to the left in an exactly horizontal direction. Immediately after he leaps, the boat of mass "M", is observed to be moving to the right at speed v. how much work did the man do during the leap ( both to his own body and on the boat)?

    is the ans as simple as " 1/2(M+m)v^2 " , or is there on to it?
  2. jcsd
  3. May 18, 2006 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Careful. It is true that the answer will be the sum of the kinetic energies of the boat and man but the man will not have the same speed as the boat. Use conservation of momentum to find the speed of the man then add the kinetic energies of the boat and man.
  4. May 18, 2006 #3
    got it! the ans is 1/2(M+(M^2/m))v^2 right? thx a bunch!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook