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: Frictional Forces acting upon a moving object

  1. Feb 16, 2010 #1
    1.A 22 kg box is being pushed across the floor by a constant force ‹ 100, 0, 0 › N. The coefficient of kinetic friction for the table and box is 0.15. At t = 8.0 s the box is at location ‹ 13, 3, −2 › m, traveling with velocity ‹ 4, 0, 0 › m/s. What is its position and velocity at t = 9.3 s in terms of an < x , y , z > vector?



    2. Δpx = -µk*FNΔt

    Δvx = -µk*g*Δt




    3. I used the formula Δvx = -µk*g*Δt and tried to solve for Vf.
    Vfx - 4 = -(.15)*(9.8)*(9.3 - 8)
    Vfx = -(.15)*(9.8)*(9.3 - 8) + 4
    Vfx = 2.089

    According to my textbook that answer should be correct, but its not. Does anyone have any tips to help me figure out what im doing wrong, or what i should do different?

    I also understand that the y and z components of the velocity are not going to change because the force is only in the x direction. So the velocity vector is going to be something like < x , 0 , 0 > i just cant figure out how to find the x value of the velocity.

     
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted