On the Applicability of Newton’s, Poisson’s and Stronge’s Collision Hypotheses

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This paper deals with collision with friction. Equations governing a one-point collision of planar, simple non-holonomic systems are generated. Expressions for the normal and tangential impulses, the normal and tangential velocities of separation of the colliding points, and the change of the system mechanical energy, are written for three types of collision in connection with Newton’s hypothesis, and for five types of collision in connection with Poisson’s and Stronge’s hypotheses. These, together with Routh’s semi-graphical method and Coulomb’s coefficient of friction, are used to show that the algebraic signs of five, newly-defined, configuration-related parameters, not all independent, span eleven cases of system configuration. For each, the ratio between the tangential and normal components of the velocity of approach, called α, determine the type of collision which, once found, allows the evaluation of the associated normal and tangential impulses and ultimately the changes in the motion variables. The analysis of the eleven cases with Newton’s hypothesis indicates that the calculated mechanical energy may increase if sticking or reverse sliding occur, and that regions of α exist for which there is no solution or there are multiple solutions. Regarding Poisson’s hypothesis, there are regions of α, narrower than with Newton’s hypothesis, for which there is no solution. However, whenever a solution exists it is unique, coherent and energy-consistent. The same applies to Stronge’s hypothesis, however for a narrower range of application. It is thus concluded that Poisson’s hypothesis is superior as compared with Newton’s and Stronge’s hypotheses.