A geometrical model of the Foucault pendulum is presented, which corrects some common misconceptions concerning the ‘‘fixed’’ plane in which the pendulum oscillates. It is shown visually, and by the use of metric geometry, that the direction of oscillation of the pendulum undergoes a parallel displacement as it moves along the Earth’s spherical surface. However, this direction of oscillation is not fixed relative to the stars.
The conservation of linear momentum and the coefficient of restitution are used to derive a formula in which the fraction of energy transferred through n bodies in one-dimensional collisions depends upon the coefficient of restitution, the relative masses of the bodies, and the number of bodies involved. The percent of energy transferred is graphed as a function of the coefficient of restitution and the number of particles which constitute a mechanical impedance-matching-taper transformer between two end particles whose mass ratio is one-hundred. A demonstration device illustrating the impedance match is discussed.
The cyclical changes in the flow properties of human cervical mucus during the menstrual cycle, and the formation of the quasi-solid cervical plug during pregnancy have been investigated subjectively during recent years. Quantitative measurements have, however, been hampered by the inadequacy of the experimental techniques available.Clift (1945) made use of an instrument (the Scott Blair menstroscope) which gave an approximate measure of a specific elastic property of the mucus. A column was partially extruded from a capillary under air pressure, which was suddenly released. The distance the meniscus returned into the capillary was measured, and was shown to vary with the time in the menstrual cycle.In a note, Clift, Glover & Scott Blair (1950) described a viscometer which by an ingeniously simple air pressure system emptied a capillary at constant speed. The machine was not altogether satisfactory in use, and the work has been repeated, using a new viscometer as improved by Scott Blair, but with a fundamental difference in technique. METHODSThe Rheometer The instrument, generously purchased for this work by Ortho Pharmaceutical, Ltd., is a commercial model of the Scott Blair (1937) capillary-tube viscometer; a schematic diagram is shown in Fig. 1.A glass capillary tube T, 3 cm long, of 0067 cm internal diameter, which carries a male threaded boss, is screwed into a socket in the rheometer, and casts an image on a ground-glass screen S with a fiducial mark upon it. A synchronous motor M1 drives the screen, together with the lens by which the image is formed, at a constant rate of 1 cm/min along the axis ofthe horizontal capillary.Pressure is applied to one end of the capillary from a uniform rubber tube R of 1 cm diameter compressed between two rollers W which are rotated by a handle, in such a way as to maintain the image of the meniscus of the fluid in the capillary tube coincident with the fiducial mark on the screen. The rollers are connected by a variable gearbox G to a stylus P which records laterally upon a drum D the change in length of the rubber tube; and thus, since the changes in length of the tube are small and Boyle's law can be applied, the extrusion pressure in the capillary is also defined. The drum is rotated at a rate equivalent to a recording speed of 4 cm/min by a second
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