Physics Help Forum Work done by friction (object pulled at constant velocity)

 Kinematics and Dynamics Kinematics and Dynamics Physics Help Forum

 Apr 7th 2012, 04:35 AM #1 Member   Join Date: Jul 2010 Posts: 70 Work done by friction (object pulled at constant velocity) My problem in understanding work done by friction proceeds reading about dissipative forces. Dissipative forces transform kinetic energy to thermal energy. Let the situation be that a box is pulled across a surface at constant velocity. Knight on p320 argues that since kinetic energy is unchanging, thermal energy is coming from "the work done on the system by the tension in the rope". But then how is there a K -> E_th?
 Apr 7th 2012, 09:44 PM #2 Senior Member   Join Date: Apr 2008 Location: HK Posts: 886 I guess the thermal energy would be lost by means of friction in reality for the one/ for the machine that keeps the box at constant velocity. That is tension in the rope is first changed to friction and then to thermal energy. But you may question that if i assume that no friction exists in all surfaces, what would be the transformation? For this one, i suspect whether in reality someone can mimic that experiment. Otherwise, it would be quite impossible for us to have a conclusion __________________ Good results were achieved and the new task is to become a good doctor.
 Apr 19th 2012, 08:20 AM #3 Senior Member   Join Date: Jun 2010 Location: NC Posts: 417 Similar Calculation might help. This example which is similar to yours: http://www.thermospokenhere.com/wp/0...te_uphill.html Might be of interest. Good Luck, JP

 Thread Tools Display Modes Linear Mode

 Similar Physics Forum Discussions Thread Thread Starter Forum Replies Last Post hongiddong Kinematics and Dynamics 4 Aug 8th 2014 11:23 AM jlyu002 Kinematics and Dynamics 5 Jul 15th 2014 10:28 AM bwill Kinematics and Dynamics 1 Nov 3rd 2009 11:19 PM bwill Kinematics and Dynamics 2 Nov 2nd 2009 09:16 PM SengNee Energy and Work 5 Jan 17th 2009 09:57 AM