Which of the following are the two forces acting on the sliders?

Question

electricity and gravity
friction and gravity
friction and electricity
gravity and acceleration
friction and acceleration

Answer 1

Probably friction and gravity. It's not at all clear what your question refers to, but an object that is sliding across a surface would normally have at least three forces acting on it: gravity, normal, and friction. Gravity is the force that all objects feel, pulling them to the center of the Earth (or the nearest celestial body). The normal force is the reaction force that typically opposes gravity, and it is a contact force with the surface below the object; the normal force always acts perpendicularly to the surface, and it can oppose forces other than gravity as well. Friction always opposes motion and is proportional to the normal force; friction cannot act on an object if there is no normal force, so it is definitely incorrect to say that only two forces act on the sliders. A sliding object may also have an applied force acting on it, but your question doesn't make it clear.