(Originais Teachy 2023) - Question Medium of Physics

A block of mass m is initially at rest on a rough horizontal floor, subject to the action of a horizontal force F that tends to move it. The maximum static friction force between the block and the floor is equal to a coefficient of static friction µ₁ times the magnitude of the normal force N exerted by the floor on the block. The block is connected to an ideal spring of negligible natural length and elastic constant k, which is fixed on the floor, and exerts an elastic force Fₓ on the block, which is opposite to the displacement of the spring relative to its natural length. The maximum elastic force that the spring can exert is equal to a coefficient of kinetic friction µ₂ times the magnitude of the normal force N, where µ₂ < µ₁. Consider g the acceleration due to gravity. Based on this information, 1) Describe all the forces acting on the block when it starts to move and then when it is in motion, indicating directions and senses. 2) Calculate the acceleration of the block immediately after the start of the movement, assuming that the block does not move vertically and that the force F is applied appropriately for the block to move. Consider the situation as a problem of Newtonian Mechanics, without considering dissipative effects such as air resistance.