1) Please have a look at Fig. 4, Fig. 5, Fig. 5A and Fig. 6. -------------------------------------------------- 1A) THERE IS NO FRICTION. (Modern technologies allow to reduce practically as much as you want the experimental error, related to friction.) -------------------------------------------------- 1B) Let us assume that the black component is fixed motionless somewhere to some obstacle and is not able to move. In this case it is evident that after entering the zigzag channel section the blue component will decelerate. And it is also evident that the deceleration d (its absolute value and its mean value) will be bigger than zero, that is, d > 0. -------------------------------------------------- 1C) It is evident that if the blue component enters the zigzag channel section, then the black component exerts force Fc on the obstacle, which does not allow the black component's linear motion. It is evident that the direction of Fc coincides with the direction of Vo. It is also evident that the force Fc (its absolute value and its mean value) is bigger than zero, that is, Fc > 0. ============================ 2) Please have a look at Fig. 1, Fig. 2, Fig. 2A and Fig. 3. -------------------------------------------------- 2A) THERE IS FRICTION in the linear channel s-segment section. -------------------------------------------------- 2B) Let us assume that the black component is fixed motionless somewhere to some obstacle and is not able to move. In this case it is evident that after entering the linear channel s-segment section the blue component will decelerate. And it is also evident that the deceleration d' (its absolute value and its mean value) will be bigger than zero, that is, d' > 0. -------------------------------------------------- 2C) It is evident that if the blue component enters the linear channel s-segment section, then the black component exerts force F'c on the obstacle, which does not allow the black component's linear motion. It is evident that the direction of F'c coincides with the direction of Vo. It is also evident that the force F'c (its absolute value and its mean value) is bigger than zero, that is, F'c > 0. ============================ 3) Please compare item 1 with item 2. It is evident that we can always choose a suitable combination of (a) magnitude of force of friction, (b) length of segments s and (c) number and shape of zigzags, for which Fc = F'c, Fc > 0, F'c > 0, d = d', d > 0 and d' > 0. Therefore it is evident that zigzags successfully imitate resistance, which is identical to friction, but without generating heat. And if we use this simple fact in the experiments, described in Figs. 1 - 6, then we can conclude again that: a) the law of conservation of linear momentum is not correct; b) the law of conservation of mechanical energy is not correct; c) both the law of conservation of linear momentum and the law of conservation of mechanical energy are not correct simultaneously. ============================ Let us stress upon the fact that IN GENERAL both the law of conservation of mechanical energy and the law of conservation of linear momentum are absolutely true and correct. There is no doubt about this. But any rule/law has its exceptions and there is nothing special, disturbing and tragic in this fact. --------------------------------------------------