Three fundamental classical laws: 1 every body continues in a state of rest or uniform motion in a straight line unless acted upon by an external impressed force; 2 the rate of change of momentum is proportional to the impressed force and takes place in the direction of the force; 3 action and reaction are equal and opposite, ie when two bodies interact the force exerted by the first body on the second body is equal and opposite to the force exerted by the second body on the first. These laws were first stated by Newton in his Principia 1687.
The down feathers found on a newly- hatched Bird.
Production of insensibility of a part by injecting an anaesthetic into the nerve or nerves supplying it.
TN for a subminiature electron tube.
Specks of solid matter in surface paint coatings, marring the finished appearance.
Test method for grading burning polymers by the amount of smoke made, measured optically.
One operating as a noise generator.
A thin homogeneous sheath investing the medullary sheath of a medullated nerve fibre. Also sheath of Schwann.
Compounds of metals with nitrogen. Usually prepared by passing nitrogen or gaseous ammonia over the heated metal. Those of Group I and II metals are ionic compounds which react with water to release ammonia. Those of Group III to V exist as interstitial compounds, having great hardness and refractoriness, eg boron, titanium, iron.
In the detection of nuclear radiation, the radiation due to natural radioactivity and to cosmic rays, enhanced by contamination and fall-out.