4.5 N is the force of friction exerted on the backpack by the table.
given:
Spring constant speing, k = 150 N/m
Extension spring, x = 3.00 cm = 0.03 m
Force=kx
Force=150×0.03
Force=4.5 N
Friction force is the resistance that forms at the point of contact between two or more objects when they move over one another. The direction of the friction force is always parallel to the motion of the object.
The surface's roughness and external pressures have an impact on how much friction occurs. The rougher the surface, the stronger the force of friction acts on it. The same is true of external elements.
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