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حبيت اسأل اللي يعرف اجابه هالسؤال اذا ممكن مساعدتي

A block slides along a horizontal tabletop.

The normal force that the tabletop exerts on the block is one half of an action-reaction pair. Which force is the other half of this pair?

1.the horizontal friction force that the tabletop exerts on the block
2.the gravitational force on the block
3.the vertical force that the block exerts on the tabletop
4.the horizontal force that must be exerted on the block to keep it sliding
5.the horizontal friction force that the block exerts on the tabletop