Agricultural Education — Examination Papers, 1885. cv 
form were hung up by one end, show in a diagram the position in 
which it would come to rest. 
3. If a body rests on an inclined plane, supported by a force acting 
parallel to the incline, explain how to find the relation between the 
ibrce, the pressure on the plane, and the weight of the body. If the 
length of the base is 12 feet and the height of the plane 5 feet, what 
force acting along the incline will support a body weighing 780 lbs., 
and what pressure will there be on the plane ? 
4. Two equal pulleys are firmly fasted to a fixed beam, so that 
their centres are in a horizontal line ; a fine thread passes over both, 
and has a weight of 3 lbs. fastened to each of its hanging ends. If 
a weight of 1 lb. is hung on to the middle of the horizontal part of 
the thread, and allowed to descend gently, in what position will it 
come to rest ? 
5. Define a foot-pound and a horse-power. 
An engine of 5-horse-power works a pumping apparatus which is 
foimd to deliver a stream of water with a constant velocity of 3 
miles an hour, and a cross section of one-fifth of a square foot, at a 
height of 40 feet above the reservoir from which the water is taken. 
What part of the power of the engine is employed in lifting the 
water, and what part in overcoming friction, &c. ? 
6. A body whose mass is 20 lbs. slides along a horizontal plane, 
the co-efficient of friction between which and the body is one-eighth. 
What resistance does friction offer to the motion ? What velocity 
does the body lose in every second ? If the body has at any instant 
a velocity of 30 miles an hour, in how many seconds, from that 
instant, will it come to rest ? 
7. If a body is partly immersed in water, what is the magnitude 
and direction of the resultant of the fluid pressures on it ? 
If one end of a floating rod is lifted out of water by means of 
a thread fastened to it, so that the rod floats in an inclined position, 
partly in and partly out of water, why will the position of the rod 
be such that the thread will be vertical ? 
8. State Boyle's Law for the pressure of gases, and describe the 
experiment by which it was established. 
A room is 50 ft. long, 30 ft. wide, and 20 ft. high ; suppose that 
at any instant the barometer stand at 29-5 in., and that shortly after 
(without any change of temperature) it rises half an inch ; how many 
cubic feet of air (at 30 in.) have come into the room ? 
9. What is the fly-wheel of a steam engine, and for what purpose 
is it used ? 
If its mean radius is 10ft., and its weight 20 tons, what is its 
accumulated work (or vis viva, or kinatic energy) in foot-pounds, 
when it makes 15 revolutions a minute? (g = 32). State how the 
" mean radius " would have to be determined for an exact answer to 
the above question in the case of a fly-wheel of given dimensions. 
