So since I can’t put the picture I’m gonna try to describe the situation:
A bunch of guys are pushing a pickup truck in one direction. There’s also a guy *on top* of the pickup truck (in the back) pushing against the front in the same direction. Obviously he’s not applying any force, but why?
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You’re close to something there with his body mass causing higher friction, but he is still exerting net zero force on the truck. The force of friction is properties to the total normal force exerted downward (the “normal force”) on the road by the total mass of the truck, which includes the forward force exerted by the man’s mass. But the force of friction is between the road surface and the truck, not the man in the bed and the truck. The normal force and the friction force are two separate forces.
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