Senior Examination Papers, 1878. 
xcvii 
O a;, 0 P, and y 0 respectively ; find their resultant by construction, 
or otherwise. 
3. A B is a uniform rod or lever, 8 feet long, weighing 10 lbs. ; it 
is cajmblc of turning freely round a hinge at A; it rests in a hori- 
zontal position on a point C, distant 2 feet from B ; what force is 
exerted on C and on the hinge at A ? What difference will there be 
in these forces (a) when a weight of 10 lbs., (b) when a weight of 
20 lbs., is hung at B ? 
4. Given three equal j^ulleys in sej^arate blocks ; describe any one 
way of combining them into a system for raising a heavy body. In 
the system described, whatever it may be, what length of rope is re- 
quired for raising the weight 10 feet ; and what power is required 
to balance a weight of 3 cwt. ? 
5. It is said that a mill working with 1-horse power can grind a 
bushel of corn in an hour ; a stream has a fall of 10 feet ; its cross 
section is 6 square feet, and its velocity through the section is 3 miles 
an hour; how many bushels of corn could it be made to grind in 
eight hours, if the water-wheel by which its power is applied can 
render useful three-quarters of the work done by the stream (i. c, 
modulus of wheel is 0'75) ? 
6. A body thrown vertically ujjwards passes a point A with a velo- 
city V , the highest point it reaches is B ; give a formula connecting v 
with the height A B and the force of gravity. 
Show that the kinetic energy or accumulated work which the body 
had when it passed A, equals the work which gravity would do on the 
the body while it falls from B to A. 
7. State the conditions that must be fulfilled when a body floats. 
A thin rod of uniform section weighs 2 lbs. ; its specific gravity 
is I ; a weight (which is to be treated as a point) is fastened to one 
end ; what is the smallest value of the w eight for which the rod will 
float vertically ? 
8. State "Boyle's Law," and describe briefly the experiment by 
which its truth can be shown. 
Is the law exactly or only proximately true ? 
The barometer stands at 30 inches ; the pressure of the air within 
the receiver of an air-pump is 4 inches ; what part of the quantity of 
air originally within the receiver has been withdrawn ? 
9. What is the radiation of heat ? If a number of things at different 
temperatures were placed in a room, which was then shut up, why 
would their temperatures tend to become equal ? Mention any circum- 
stance that occurs to you as likely to prevent this tendency from 
having full effect. 
