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!

Question about static friction and energy loss

  1. Jan 10, 2012 #1
    I know static friction can cause an object to accelerate, but also decelerate.
    And i also know that static friction never cause energy loss, but I wonder when it causes an object to decelerate, its kinetic energy should decrease, so where is the mechanical energy gone? Has static friction done work on the object? Thank you!
     
  2. jcsd
  3. Jan 10, 2012 #2

    Doc Al

    User Avatar

    Staff: Mentor

    Please give a specific example of what you have in mind.

    For example, a car slowing down. Assuming the tires do not slip, it is static friction from the ground that slows the car. (Ignoring air resistance, etc.) But that static friction does no work. The mechanical energy of the car has gone into internal energy within the car (the brake pads, for example).
     
  4. Jan 10, 2012 #3
    My textbook says
    When a box is placed on a travelling truck , and then the truck brakes to stop, the deceleration of the box is because of the static friction. (There is no sliping occurs)

    I am confused because the box's K.E. should decrease to zero, and I have no idea how and where the mechanical energy is taken away. Is it converted into internal energy of the box?
     
  5. Jan 10, 2012 #4

    Doc Al

    User Avatar

    Staff: Mentor

    OK.

    The box's KE does go to zero when the truck stops. You can just think of the box and just another part of the truck. All of that mechanical energy ends up as internal energy within the truck.
     
  6. Jan 10, 2012 #5
    Thank you so much !!:)
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Question about static friction and energy loss
Loading...