At the first face of a parallelepiped-shaped bar, the friction coefficient against the table is 2 times greater

At the first face of a parallelepiped-shaped bar, the friction coefficient against the table is 2 times greater than that of the face. According to the law of dry friction, when the bar is turned over from the first face to the second, the friction force on the table 1) does not change 2) decreases 2 times 4) increases by 2 times 3) decrease by 4 times

The dry friction force is determined by the formula Ftr = kmg, where k is the coefficient of friction, m is the mass of the bar, g is the acceleration of gravity. When the bar is turned over from the first face to the second, the mass of the bar and the acceleration of gravity remain unchanged, and the coefficient of friction becomes half as much. Accordingly, the friction force of the bar against the table will be halved.