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!

Work problem

  1. Nov 3, 2005 #1
    Hi, I'm having problems with this question:

    ok first I determined what work that gravtity does which is m*g*(delta y) which in this case is -50 J

    I then used the CEW theorem equation using the velocities to find the total work done: (sigma W) = 1/2 m (v^2 (final) - v^2(initial)) which is -62 J

    Last part is that I used the relationship between the work of gravity and the total work (sigma)W = W of gravity + Work of air resistance. I got -12 Joules for air resistance. I don't know but I feel like I got something wrong here. Can anyone help me out?
  2. jcsd
  3. Nov 3, 2005 #2


    User Avatar
    Homework Helper

    Well, the difference between the kinetic energy at the bottom and the potential energy at the top will be the amount lost due to air resistance.

    E_a = (1/2)mv^2 - mgh = 61.7 - 50
    = 11.7J

    W_a = E_a
    = 11.7J

    I don't know the method you have used.

    Edit: Work is a scalar I see.
    Last edited: Nov 3, 2005
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Threads - problem Date
Problem related to Bernoulli Equation Today at 4:27 AM
Stability of a wedge problem Yesterday at 12:42 PM
Heat capacities problem Monday at 3:19 AM
Physics Word Problem: Arrow and moving target collision Saturday at 10:55 PM
Electric potential problem Saturday at 3:09 PM