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shrutij
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Homework Statement
A 15.6 kg block is dragged over a rough, horizontal surface by a 68.9 N force acting at 19.7 degrees above the horizontal. The block is displaced 4.59 m, and the coefficient of kinetic friction is 0.286. Find the work done by the 68.9 N force.
How much energy is lost due to friction?
Homework Equations
W=F (Δr) cos∅
Friction (kinetic)= μk* m*g
The Attempt at a Solution
I found the work done by the 68.9 N force using the equation above to get 297.74 J.
The energy lost due to friction should be simply the Force of kinetic friction multiplied by the displacement, right?
I did 0.286*15.6 kg* 9.81 to get 43.77 N as the force of kinetic friction.
Energy lost= Force friction * displacement i.e. 43.77 N * 4.59 m = 200.90 J, which is wrong.
What am I missing?