xxii Agricultural Education — Examination Papers, 188(i. 
A rod of uniform density weighing 20 lbs. can turn freely round 
a hinge at one end ; the other end rests against a smooth vertical 
wall ; the rod is inclined at an angle of 45' to the horizon ; find the 
pressure on the wall. 
4. Describe briefly the wheel and axle, and find the i-elation 
between the power and the weight, when they keep it in equilibrium. 
If the radius of the axle is 5 in. and that of the wheel 2h ft., what 
power will be required to balance a weight of 840 lbs. ? If the 
wheel and axle and the ropes weigh 300 lbs., what will be the whole 
pressure on the bearings that support the machine ? 
5. A. body is observed to increase its velocity in every second by 
5 ft. a second ; how far would it move from a state of rest in 12 
seconds ? If the mass of the body is 1-5 lbs. what is the numerical 
value of the force which produces the motion ? How many pounds 
of matter would that force support against gravity at a place where 
g = 32°. 
6. State one method of determining the specific gravity of a liquid. 
Two gallons of a liquid whose specific gravity is 0'9, are mixed 
with three gallons of a liquid whose specific gravity is 0-8 ; assuming 
that the mixture takes place without expansion or contraction, find 
the specific gravity of the mixture. 
7. Mention briefly the reasons for believing air to be a heavy 
elastic fluid. 
A bladder partly filled with air and tied tightly, so that none of 
the air can get out, is put under the receiver of an air pump ; it is 
well known that if the air is partly withdrawn from the receiver the 
bladder swells out ; what property of air does this demonstrate ? 
8. Describe briefly the mercurial barometer in its simplest form. 
A barometer, whose tube is 32 in. long above the surface of the 
mercury in the cistern, is found to read 27 in. when the true reading 
is 29 in. ; what may it be expected to read when the true reading is 
30 in. ? In what way would the reading of the faulty barometer be 
affected by change of temperature ? 
9. Describe briefly one method, commonly used, for converting the 
up-and-down motion of the piston of a steam-engine into the con- 
tinuous rotation of the axle which carries the fly-wheel. 
10. The area of the piston of a steam-engine is 5000 square in., 
and the stroke is 8 ft. long ; the mean pressure of the steam is 
12 lbs. per square inch ; how many strokes are made per minute 
when the machine works with 160 horse-power? 
