|
|
As you say when pushing a book, the work that you do "against friction" is apparently lost - it is certainly not available to the book as kinetic energy! Forces that do not store energy are called nonconservative or dissipative forces. Friction is a nonconservative force, and there are others. Any friction-type force, like air resistance, is a nonconservative force. The energy that it removes from the system is no longer available to the system for kinetic energy.
So, how is not clear that [A] is not the answer as it includes non-conservative forces
EDIT : Hmm well I thought about it. Consider you throw a block on a rough surface. So, initial kinetic energy is +ve. Friction acts on it and reduces K.E. to 0. So, there is change in K.E. So, answer could be [A]. I agree.
|
Moderation Team
![[Post New]](/templates/default/images/icon_minipost_new.gif){kind=icon}
![[Up]](/templates/default/images/icon_up.gif "[Up]"){kind=icon}
152
1
