1971-12-01 — Page 19

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育教傕華頁三筅弦王第四十月十年均年層夏IAH KIN YAT PO

報日橋草

-10EC197

ETS B

CITY HALL

户二十年一七九一公年十六國中

(接第五張第二頁)

育敎僑華

Consider M

alone, the following equations

1972中學入學試試題預習專欄

智慧出版社主编

can be written for each in, tura

-(1)7

英文科

(五)

1972英文中學會考試題預習專欄

-(2)

The inspector asked me

ticket.

Resolve all the forces parallel to two, dirao- tions x and y at right angles to one another. The algebraio sum of all the foroes in the e direction must be zero, and likewise the lgebraic sum of all the forces in the y dir votion must be zero.

Take moments of all the forces about any exis perpendicular to the plane of the forces. The algebraic sum of these moments must be

Zaro.

If the forces satisfy conditions (1) they will produce no motion of translation while (ii) is the condition that the forces shall produos no rotation.

堅道英文書院主編

物理科

(五)

Physica (5)

Eliminate

from (1) and (2)

(5) (a) For the equilibrium of a rigid body under the

action of coplanar forces, the following cond- itions are necessarys,

·8 - M1a - T + {{}_3

timi

from (3) and (4)

- M1a - (M2a + M28)

• He took off his hat

3. My brother

John Is

excited

Nobody knows

had bought my

he entered the

Azkes. fishing very much.

he can hardly say

the prisoner escaped.

You will not get better

doctors advice.

you follow the

·wine"

ུ།

tobacco is good for young people.

they lert

8. Hong Kong has changed a lot

Canada.

9. Please don't leave here

10. The visitor left the room.

manager

I come back.

he had

III. In each line there are two sentences. Join them..

together, using the word or words in the bracketay and make other changes where necessary. Example: John likes fishing. John likes, swimming.

(both

John likes both fishing and swimming,

1. This is the place. The accident happened an toa#-

place. (where)

Ecos60

T be the tension in the string and

R the reaction at the hinge

aking moments about A,

Toos60 x AB - 4 ≈ A‍+ 10 x AB

24

saolva the forces vertically and horizontally,

B cos. + T.co860 - 4-7 10.

Q

" #in60

R.009

Ex

R2coa2 + R2sin2 = 4 + (12)3

{ 2 (008 A+ sin A)

+ 432

436

20.91

gain60

7600

Fig. (1).

Jonsider

5 kg mass and 6 kg masa alone respectively (Fig. (2) and Fig. (3))

<Resolve forces along and perpendicular to the plane

gain60

[Ag(2)]

0960

-(1).

-(2)

-(414)

(iv)

·Fig. (3),

30

-(4)

-(5)

The room is big. The moon is com

(not only

Hib

Brother is not present

The boy was very tired.

He fell as

asleppe

ishes her.

(as soon as

She

catch the

باند

ke

5sin60

681n30

500860

600830

0.169

The coefficient of friction between the planes and the masses – 0,17

(iv)

(iii)

sin

CON

tan →

10.32

The tension in the string, 18 24 kg-wt. zand the reaction at the hinge is 20.9 kg-wt. inglined at an angle of 84.5 to the verticna

(11))

Substituting

into (1) and eliminating R

jesin60

-(7)

Similarly,

From equations (3), (4) and (6)

Fliminate

and (8)

M1geinco IN 2009.30 + gain30 + fi, goo§00

118(M, 20960 + M ̧cos30) = g(sin60

160 - M sin30)

(M,sin60 - M,sin30)

M2cos 30)

(M, cos50 +

Problems for nex issue

(7) (a) State Archimedes Principle

(b) A centimetre cube of lead and a cork of volune-

45 .c. are in equilibrium on the pans of small balance in air of density 1.25 gm. par litze. The balance is placed under a ball-jar which is completely evacuated. Which body will. now be heavier and by how much?

(8) (a) Deduce the relation between the initial and final velocities and the distance travelled for a body moving with uniform acceleration. (b) A baloon 13 llú m above

m above the sea and is ascend- vertically. A body is droppad from the balcon and reaches the sea in 5 sec. What is the. velocity of the baloon. When it strikes the water the body loses half of its velocity. The weight of the body is 0.7 of that of an equal volume of sea water. Neglecting any resistances due to the movement and friction of water, find how far the body will sin before it comes monentainly to rest.