Consider two observers who are in different inertial reference frames.?

Consider two observers who are in different inertial reference frames that move with velocity (v) with respect to each other. They both observe an object being pulled on a rough horizontal surface. Do they agree as to the value of a) the object's kinetic energy, b) the total work done on the object, (c) the amount of energy transformed from mechanical to thermal energy due to friction? Does your answer (c) contradict (a) and (b). Explain.





Please help, this is from chapter 8 of a physics textbook on conservation of energy, potential energy, and power. Thanks!

Consider two observers who are in different inertial reference frames.?
a) no. object speed is different for the two observers, then it's kinetic energy is different.





b) no. the force is the same, but the displacement is different.





c) yes.





The work done by the friction force on the object is different (because the displacement is different), by so is the work done by friction force on the surface. As the difference of the displacements of the object and the surface is the same for both observers (even if the displacements are different), the addition of the work of both friction forces is the same for both observers.
Reply:i suppose,


since both are in the inertial frame the K.E n work done and friction should be same ,observed by both the frames.