Law Conservation of Energy: Starting off a solution for 11b

[Jigga]

Homework Statement

Homework Equations

ΔE_system + ΔE_surroundings =0

The Attempt at a Solution

I have solved 11a and got 5m/s.
I can do 11b just by just jumping to E_k = Fs (from the work kinetic energy theorem), but I would like to do it formally from first principles using the Law of Conservation of Energy.
I would then like to make use of
ΔE_system + ΔE_surroundings =0
and then make use of ΔE_system = ΔU + ΔE_k + ΔE_p
and then make use of ΔU = W + Q
and then introduce W = Fs
then solve for F.
However I am not sure where to put the system boundary so this is solvable. Then the question of the pluses and minuses.


Many thanks

 

[CWatters]

Depending on where you draw the system boundary the heat generated by friction will either remain within the system boundary (part of Delta E system) or cross the boundary (part of Delta E Surroundings) either way it's solvable.