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: Physics help -- pushing a refrigerator across a wooden floor

  1. Oct 8, 2014 #1
    I did attempt the problem, but I' now more confused than ever. Please help me.

    Joe is moving his refrigerator to take to college and he begins by pushing it across
    the wooden kitchen floor.

    On a flat surface like the floor, how do you calculate how hard he needs to push?

    Draw a free body diagram to help explain your answer and use the simulation Ramp:
    Force and Motion to check your ideas.
    1.Record the minimum force Joe would have
    to use to move the refrigerator on the kitchen floor.

    2. Later, Joe is ready to load his refrigerator onto the moving truck.

    a. Explain how he would calculate how much force to use to lift the refrigerator straight
    up into a truck.

    b. Joe starts thinking about easier ways to get it in the truck and remembers he has

    some wood that he could use to make a ramp. How could he calculate the minimum

    force needed to push it up the ramp?

    Sorry I've been stuck on this for an hour :(

    By using these...:
    (kinetic/ sliding) mu=0.2
    mass= 200kg
    Normal Force= 2000N
    Last edited: Oct 8, 2014
  2. jcsd
  3. Oct 8, 2014 #2
    Do you know the refrigerator's mass?
  4. Oct 8, 2014 #3
    200 kg
  5. Oct 8, 2014 #4
    So, first you would calculate the gravitational pull: G=gm, where g=9.8m/s
  6. Oct 8, 2014 #5
    G= 200kg * 9.8m/s^2 = 1960N?
  7. Oct 8, 2014 #6
    Oh, wait! I did not see that you changed your original thread!
    Actually, first since the normal force is 2000N, the gravitational force is also 2000N.
  8. Oct 8, 2014 #7
  9. Oct 8, 2014 #8
    Then, to find the sliding friction force, you would do: Sliding=normal force x mu
  10. Oct 8, 2014 #9

    so, mu=force of friction/ force of newton, right?
  11. Oct 8, 2014 #10
    mu is .2 from your original thread!
  12. Oct 8, 2014 #11

    Okay, I understand that mu = .2 and g= 2000N. What I don't understand is how to solve the problem.
  13. Oct 8, 2014 #12
    So, you just multiply them together resulting in the numerical value for sliding friction
  14. Oct 8, 2014 #13

    Ohhh...Waw! Thank u!
  15. Oct 8, 2014 #14
    The sliding friction answer is the equivalent to the minimum force needed to push the refrigerator! (answer in Newtons)
    And Your Welcome!
  16. Oct 8, 2014 #15

    Sorry...can I have more help with just two more questions? Please.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted