Projectiles, pendula, and special relativity

The kind of flat-earth gravity used in introductory physics appears in an accelerated reference system in special relativity. From this viewpoint, we work out the special relativistic description of a ballistic projectile and a simple pendulum, two examples of simple motion driven by earth-surface gravity. The analysis uses only the basic mathematical tools of special relativity typical of a first-year university course.Comment: 9 pages, 5 figures; to appear in American Journal of Physic

Cnemidophorus tesselatus

Number of Pages: 2Integrative BiologyGeological Science

Phrynosoma cornutum

Number of Pages: 7Integrative BiologyGeological Science

Cooling of High Pressure Rocket Thrust Chambers with Liquid Oxygen

An experimental program using hydrogen and oxygen as the propellants and supercritical liquid oxygen (LOX) as the coolant was conducted at 4.14 and 8.274 MN/square meters (600 and 1200 psia) chamber pressure. Data on the following are presented: the effect of LOX leaking into the combustion region through small cracks in the chamber wall; and verification of the supercritical oxygen heat transfer correlation developed from heated tube experiments; A total of four thrust chambers with throat diameters of 0.066 m were tested. Of these, three were cyclically tested to 4.14 MN/square meters (600 psia) chamber pressure until a crack developed. One had 23 additional hot cycles accumulated with no apparent metal burning or distress. The fourth chamber was operated at 8.274 MN/square meters (1200 psia) pressure to obtain steady state heat transfer data. Wall temperature measurements confirmed the heat transfer correlation

Development of high voltage - High current switches Final report

Envelope, electrode, and trigger design for high voltage high current switc

The Controversy over Maltby’s Hong Kong Dispatch

The recent release of the full text of Major-General CM. Maltby’s Official Dispatch as the General Officer Commanding at Hong Kong (Public Record Office WO 106/240113) prompted British and Canadian newspapers to run sensational stories quoting Maltby’s criticisms of the discipline and battlefield performance of the Canadian battalions. Maltby’s statements, which were censored when the Dispatch was initially released, require a detailed examination and will be discussed in a future issue of CMH. In addition, the Spring 1994 issue will carry an article by Paul Dickson on “Crerar and the Decision to Garrison Hong Kong.” For the present we are publishing an exchange of correspondence, dated January 1948, between Lieutenant-Colonel G.W.L. Nicholson, then Deputy Director of the Army Historical Section, and Brigadier John H. Price who was second-in-command of the Royal Rifles of Canada in Hong Kong. Brigadier Price was asked to comment, not on the censored Dispatch, but on extracts from a draft report prepared by the Historical Section of the British Cabinet Office. This report contained the substance of the most serious charges Maltby made about the conduct of the Royal Rifles. For the information of the reader, other officers mentioned in the exchange include Brigadier C. Wallis, Indian Army, commander of the East Brigade (to which the Royal Rifles belonged), Lieutenant-Colonel W.J. Home, commander of the Royal Rifles, Lieutenant-Colonel J.L.R. Sutcliffe, Commanding Officer, Winnipeg Grenadiers, Brigadier J.K. Lawson, Commanding Officer, “C” Force (as the Canadian contingent was known) and Colonel P. Hennessy, Lawson’s second-in-command