1973-05-16 — Page 21

報日僑華

育教低華,頁一第張六第日四十月四年丑癸展 VOAKIUYAT PO

三期星®

日六十月五年三七九一曆 公年二十六國民華中

僑

Find the tension in the strin in fig

19. A metal rod of R.D. = 8 floats-

upright in a liquid of R.D.

Smooth

10. What is the fraction

of length submerged?

wall

Smooth

4kg

pulley

P.

1973英文中學會考試題預習專欄 *

那道熊文書院主編

物理科

(三十)

smooth table.

the who wh

min alm

rough ground

Physics (30)

Revision Exercise I (on Mechanics, neat and sound

1. Consider a simple pendulum.

Which of the following is not correct?

equilibrium position

The string is light and. inextensible.

B. The bob suspended by the string must be small and heavy

One complete oscillation is the motion from A to B to C D. The amplitude is the maximum

displacement from the

equilibrium position.

The period depends only on the length and the gravity provided that the oscillat- ion is small

Which of the following is. correct?

A. A vector is a force. B. A vector is a fundamental

quantity in physics.

A vector is a quantity that can be measured.

A vector is a quantity which

can take on positive and negative values..

A vector is a quantity which has both magnitude and direction.

An object is acted on by 31

non-parallel forces.

the

following:

(1

Consider

they are concurrent. (ii) they are coplanar..

(iii) they can be represented by vectors forming a triangle taken in order.

(iv) their resultant is zero. Which of the following gives the necessary and sufficient condition for the e object to be in equilibrium?

A. I, III IV

B. I, III

C. II, III

D. I, II

E. None of the above

Which of the following is a vector?

A. energy

B power

O speed

D. impulse

E. density

5. A stone is projected vertically upward with a speed V and some- time later a second stone is thrown upward from the same place.

Suppose they meet in air Then when they meet, they have the same speed.

the

B. they have travelled through

equal distances.

C. they have spent the same

period of time.

D. they have equal mechanical

energy.

E. they have the same direction

of motion.

6. If the uniform ladder is in

equilibrium, what is the co- efficient of static friction between the ladder and the ground.

cannot be determined because W is not given..

cannot be determined because the limiting friction is not "known.

In fig 3, the ladder is unifor and is in equilibrium. R is the reaction at the ground. What is the inclination of the reaction to the horizontal?

P. 60°

R. 300

Q450 S. 909

T. cannot be determined.

k2m

smooth

wall

A horizontal force of 4 kgf required just to move up a wooden block of mass 3 kg up

a plane inclined at 45° to the horizontal.. What is the co- efficient of static friction between the block and the plané

3√3

A unifom wooden block rests on

a rough incline whose inclinat -ion can be varied. What is the inclination when the block just topples over?

mist inim

If in question (9), the co- efficient of static friction between the block and the plane is 0.6, and the angle of inclination of the plane is gradually increased, find which occurs first, toppling or slipping?

P. Toppling

Q. slipping. R. Toppling and slipping occur

simultaneously.

S. cannot be determined because

the area of contact is not given.

cannot be determined because the weight of the block is not given.

A bullet of mass m kg and speed V m/s is brought to rest int seconds by a wooden target. The depth penetrated in metres is

1. Vmt

Vt

Vt

B. Vt

2Vt

M

12. An object is uniformly acceler ated from rest at a rate of

2 m/s2. Find the distance

traversed in the 4th second.

A. 6 m. C. 8 m. E.. 10 m.

B. 7. m. D. 9 m.

20.

kgf

0.4 kgf

B. 0.2 kgf

0.25 kgf

1. 3 kgf

13. A man of mass 50 kg is stand-

ing in a lift which is acceler →ating upward at a rate of 5 m/s2 floor.

N.

C. 500 N.

E 125 N.

The reaction of the

B. 750 N.

D. 375 N.

14. A bullet of mass 0.004 kg is

fired from a gun of 5 kg with a speed of 500 m/s. The recoil velocity of the gun is

• 10√2 m/s, same direction as the bullet."

B. 10 2 m/s, opposite direction

to bullet.

0.4 m/s, same direction as bullet.

D. 0.4 m/s, opposite direction

to bullet.

E. cannot be determined because

a certain amount of energy is converted into heat.

E.

What is the V.R. of the system of pulleys shown in fig 67

Effort

Load

16. If in question (15) the load

is of mass 48 kg and the lower block weighs 4 kg, what is effort if the efficiency of. the machine is 80%?

11 kgf. R. 13 kgf

T. 41.6 kgf

Q. 12 kgf S. 8.32 kgf

17. 1 volume of a liquid of R.D. 4 is mixed with 3 volumes of a liquid of R.D. 2. Assuming no contraction, the R.D. of the mixture is

R. 5

12

2.5 10

18. As shown in fig 7, if the

plate is at the point of falling off, what is the density of the oil?

-oil

in question (19), water is poured onto the liquid until the rod is just below the water surface, what is the ratio of the length submerged in water to that submerged in the liquid?

WIN WIN NA

In an oil-film experiment

is found that a m of a certain oil gives a film of diameter b m. The length of the molecules of the oi is approximately

2a

По

по

22. In a (constant volume) gas

thermometer, the pressure at the lower and the upper fixed points are 70 cm and 95 cm. of mercury respectively. What temperature corresponds to a pressure of 140 cm. of He? A 280°K

B. 546 K C. 5539K

E.

413°K

D. 148°K

23. A substance expands when heat

-ed". This statement is

Always true.

B. false

C. usually true,

exceptions.

but with

D. usually false, but wit

exceptions.

E. None of the above

24. A brass plate has an egular:

hole drilled in it. The area

22

of the hole is 100 cm, a 0°C What will be its area at 100°C

A. 100 cm

cm2

C. 100.36 cm

99.64 cm

D. cannot be determined cause

the shape of the hole unknown.

cannot be determined because, the dimensions of the plate is unknown.

A U-tube containing a liquid has one limb surrounded by ice at 0°C, and the other limb by hot water at 50°C. The height of the liquid columns in the limbs are 50 cm. and 54 cm. respectively. What is the co- efficient of real expansion of the liquid?

A. 1.2 x 10 100

B. 1.6 x 10/06

C. 1.4 x 10-4/00

D. 1.8 x 10 400.

E. 2.0 x 10-400.

water

26. What is the length of the air column? (atmospheric pressure. 75 cm. of Hg)

1-30 +15+

plate

Q. 333 kg/m3

P. 25 cm.

P. 500 kg/m3

R. 250 kg/m3 S. cannot be determined because

the cross-sectional area is not given.

T. cannot be determined because

the atmospheric pressure is not given.

R. 30 cm.

T. 22.5 cm.

50 cm. S. 5 c

cm.

27. The volume of a gas is 1 litre

at 27°C. At what temperature. will its volume be 1.5 litres if the pressure is doubled?

(未完轉入第六張第四爽 )