Presents an experiment that uses the measurements of the impulse required to stop a moving mass by three different methods to demonstrate that regardless of whether the maximum force is large or small, approximately the same impulse is required. (JRH)

Develops a theory of gravitation which is a natural extension of the Newtonian theory. It is compatible with special relativity and with all present-day observations. It requires only elementary mathematics and can be taught in a junior level mechanics course. (Author/MLH)

Describes a method to eliminate the nonlinearity from a spring that is used in experimental verification of Hooke's Law where students are asked to determine the force constant and the linear equation that describes the extension of the spring as a function of the mass placed on it. (JRH)

Defining "force" in everyday terms is not a simple matter. Discusses experience with various examples and shows that it is useful to examine whether students have indeed grasped the correct meaning. (Author/MM)

Finds a strange behavior that contradicts the common notion that the force of kinetic friction is constant and depends only on the normal force. (CCM)

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

Describes a laboratory experiment on surface tension. (Contains 14 references.) (YDS)

Applies Newtonian mechanics in an analysis of how a swing is made to move. (GS)

Explores the basic physics behind pulling a tablecloth out from under a set of dishes, glassware, and utensils without disturbing them. Discusses terminology of Newton's laws of motion and illustrates them using three simple examples. (NB)

Suggests that physics students always have three questions when using force diagrams: (1) Why do I need one? (2) How do I draw one? and (3) How do I find the forces acting on a body? Provides a method to help students find answers to all three questions and understand force diagrams. (MVL)

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)

Photographs show three simple demonstrations of deceptive centers of gravity. (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)

Offers suggestions concerning the use of the concepts weight, mass, and force with the adoption of the International System of Units (SI) in the United States. (CP)