The theory of canonical transformations and its development are discussed with regard to its application to Hutton's principle. Included are the derivation of the equations of motion and a lack of symmetry in the formulaion with respect to Lagrangian and the fundamental commutator relations of quantum mechanics. (Author/SA)

An algebraic definition of time differentiation is presented and used to relate independent measurements of position and velocity. With this, students can grasp certain essential physical, geometric, and algebraic properties of motion and differentiation before undertaking the study of limits. (Author)

Describes an experiment to measure the effect of air resistance on falling balls suitable for use in undergraduate physics courses. (PR)

Explains a physics experiment on the dynamics of impact cratering. Measures the spreading velocity of the impact wave and the acoustic signal. (YDS)

Provides a physical description of motion resulting when force is applied perpendicular to the axis of rotation on a gyroscope. (SL)

Describes a laboratory activity about measurement and its reliability for general education students. The measurement focuses on automobile speeds and allows for estimates of errors, experimental design, and relativity in addition to kinematical concepts. (DS)

Provides an analysis of the forces causing the erratic motion of a knuckleball. Reveals the manner the ball should be thrown to provide maximum deflection. (Author/CP)

Presents a simple means for extending the Bohr model to include relativistic corrections using a derivation similar to that for the non-relativistic case, except that the relativistic expressions for mass and kinetic energy are employed. (Author/GS)

An analysis of the minimum stopping distance problem is presented taking into account the effect of weight transfer on nonskidding vehicles and front- or rear-wheels-skidding vehicles. Expressions for the minimum stopping distances are given in terms of vehicle geometry and the coefficients of friction. (Author/BB)

Reviews Galileo's experiments with falling bodies conducted at the Tower of Pisa. Results indicate it is doubtful that he could have obtained the results claimed in the legend. (SL)