I'm confused about how Newton's 3rd law applies to friction. If you slid an object across a table then the particles you are sliding against would exert the same force back, but wouldn`t this mean constant velocity since the object has equal acceleration in opposite directions, but it isnt really a force to begin with since if its sliding by itself then you are no longer exerting a force, the only force is the force of friction?
Please help, keep in mind Im new to physics and I only know the basics of newtonian laws.