Ans
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Here used the basic work energy theorem which states that work one by allall the forces= change in kinetic energy
So here work done by gravity is
mg * length of the incline sin thita
And work done by friction
Add these two
And equate it with change in kenergy
U got ur answer
As per ur opinion final mechanical energy is k.e plus p.e that's absolutely correct but it is consequence of the work energy theorem which states that
Mechanical energy is constnt if there is no work by any nonconservative force
Still u have any problem then don't hesitate to ask
hope it will help u
8 years ago
by
ansuman dixit