A web-based interactive virtual experiment on the subject of conservation of angular momentum is presented. Students can perform the virtual experiment anywhere via the web before executing the actual physical experiment in a laboratory. The virtual experiment is designed to incorporate factors and parameters that could be estimated or fixed arbitrarily, or to be varied based on the results of the physical experiment. Students will then have a better understanding of the limitations of a virtual experiment and how a physical experiment could help to refine the corresponding virtual experiment.

Based on the analytical solution of the equation of motion for a single degree-of-freedom model of a spring, the relation between the dynamic behavior and the kinematic features of input cam motions is discussed in this paper. A simple expression for the dynamic response spectrum of the vibration excited by the input motion is presented. It provides a useful tool to estimate the effect of cam motions on the dynamic behavior of springs. A method for the selection of cam motion curves based on this response spectrum is also presented in the paper. Examples are given to illustrate the method.

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To analyse the motion of a rigid body sliding along a rough surface, information on the point of application of the resulting frictional and normal forces is usually not required. The present study proceeds further, by finding the direction and point of application of the resulting frictional and normal forces on a rigid body in planar motion. These findings are usually omitted in traditional analyses of these problems. It will be shown that such a sliding motion, which is assumed to be feasible with the finding of the acceleration, is not possible for certain combinations of coefficient of friction and geometry of the rigid body. Some interesting findings are highlighted and discussed.

The radius of curvature of a cam profile is an important factor that affects the working life of cam mechanisms. Based on flexible motion curves using parametric polynomials developed earlier, a method for maximizing the minimum radius of cam curvature using a nonlinear programming technique is presented. The relation between the radius of curvature of a cam and the kinematic features of the corresponding motion curves is discussed. Examples are presented to illustrate the method.