The Bondi K-calculus is a delightful method that has been used to provide rich insights into relativistic kinematics. In this paper, we will try to show how several important results of relativistic kinetics can be derived simply by using this approach. In addition, we will also indicate how the K-calculus can be used to simplify certain…

Preverbal infants can represent the causal structure of events, including distinguishing the agentive and receptive roles and categorizing entities according to stable causal dispositions. This study investigated how infants combine these 2 kinds of causal inference. In Experiments 1 and 2, 9.5-month-olds used the position of a human hand or a…

Using a continuous tracking task, the authors examined whether stopping is resistant to expectancies as well as whether it is a representative measure of response control. Participants controlled the speed of a moving marker by continuously adjusting their response force. Participants stopped their ongoing tracking in response to auditory signals…

Samar and Parasnis [Samar, V. J., & Parasnis, I. (2005). Dorsal stream deficits suggest hidden dyslexia among deaf poor readers: correlated evidence from reduced perceptual speed and elevated coherent motion detection thresholds. "Brain and Cognition, 58," 300-311.] reported that correlated measures of coherent motion detection and perceptual…

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)

The circular motion observed when water drains into a smooth opening is analyzed. This action, as well as cycloidal atmospheric motion, is explained as the result of rotation of the coordinate system. (CP)

Discusses topics such as streamlined flow, turbulent flow, velocity profiles, and drag reduction as background information for the consideration of the use of drag reducing agents. (GS)

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)

In this note, we introduce a simple homemade toy called the brush-creeper, which can glide forward with no propellers, limbs, wheels, and seemingly no movement of any kind that can push forward against the ground. The toy arouses pupils' interest and their incentive to ask "Why?" in lessons related to friction.

This study of the relationship of computer technology to character animation focuses on the advantages and constraints of developing three-dimensional characters for computer animation. Three different levels of the complexity involved in animating characters are examined: (1) a three-dimensional computer environment and simple motion within this…

Shows how physics can be used to analyze and prevent traffic accidents by determining critical speeds on curves, the behavior of motor cycles and stability of articulated vehicles, and the visibility that is needed to make a minor road junction safe. (MLH)

Reviews the equations of motion and the use of a sine-sine coordinate grid for convenient plotting or analyzing of Lissajous figures. (Author/GS)

This paper deals with research on the development of infants' ability to perceive invariant features of things and the relation of objects to both the spatial layout of the infants' environment and to themselves. Basic assumptions regarding the perception of invariance are discussed and a theoretical view of the role of motion in the development…