cii Agricultural Education — Examination Papers, 1880. 
EXAMINATION IN MECHANICS AND NATURAL 
PHILOSOPHY. 
Maximum Number of Marks, 200. Pass Number, 100. 
Thursday, April 15th, from 10 a.m. till 1 p.m. 
1. State the conditions of equilibrium of three forces acting on a 
particle. 
Show by a construction or otherwise how forces of 12, 15, and 24 
units must be adjusted so as to keep a particle at rest. 
2. State briefly how force is transmitted along a thread. 
A body weighing 5 lbs. hangs from an end of a thread ; if I push 
my finger against the thread so as to bring the upper part into an 
inclined position, while the lower part (of course) hangs vertically, 
how would the pressure on my finger be found ? In what position 
would the pressure exactly equal the weight ? 
3. The handle of a hammer is 15 inches long and weighs ^ lb. ; the 
head weighs 2 lbs. ; the centre of gravity of the handle is in its 
middle point, and that of the head is i inch from the end of the 
handle ; where will the centre of gravity of the hammer be ? 
4. It has been ascertained that a man acting on a winch can do 
work at the rate of 1,200,000 foot pounds of work in a day of 8 houi's. 
If two men can lift a ton through 15 feet in 10 minutes, by means of 
a properly constructed crane, how much of their work is wasted on 
friction ? 
5. When is the velocity of a body said to be uniformly accelerated '? 
If the acceleration be 10 when the units are feet and seconds, what 
distance will the body describe while its velocity is increased from 
11 feet a second to 44 feet a second. If the mass of the body is 
100 lbs. what force would be required to produce the acceleration ? 
6. Describe the hydrometer in any one form. An ordinary hydro- 
meter, whose stem is of uniform section, sinks to a certain point A in 
distilled water, and to another j^oint B in a liquid whose specific 
gravity is 0-96 ; find, in terms of A B, the distance from A to the 
surface when the hydrometer is placed in a liquid whose specific 
gravity is ^ths. 
7. Distinguish between heat and temperature. Mention any cir- 
cumstances in which heat may be communicated to a body without 
changing its temperature. 
8. State the relation between the volume, pressure and temperature 
of a given quantity of gas. A cubic foot of dry air is inclosed, 
without compression or rarefaction, when the thermometer stands at 
60° P. and the barometer at 30 inches ; if the temperature of the air 
is raised to boiling point without change of volume, what pressure 
does it exert per sqiiare inch on tlic surface that incloses it ? 
9. Describe briefly the steam indicator, and how the indicator dia- 
gram is drawn and what it indicates. 
