When an object with mass m is placed on a rough horizontal plane, its dynamic friction force is u. under the action of constant force F, it moves in the horizontal direction, and the displacement s, F and the horizontal direction a are the same Find (1) the work done by each force (2) Find the total work of these forces on the object (3) Seeking external force (4) Total work done by combining external forces

When an object with mass m is placed on a rough horizontal plane, its dynamic friction force is u. under the action of constant force F, it moves in the horizontal direction, and the displacement s, F and the horizontal direction a are the same Find (1) the work done by each force (2) Find the total work of these forces on the object (3) Seeking external force (4) Total work done by combining external forces

Friction work - U (Mg-F * Sina) s
F works f * cosa * s
Total work f * cosa * S-U (Mg-F * Sina) s
Combined external force f * cosa-u (Mg-F * Sina)
The total work of the latter is the same as that of the former