Bài 16. Ròng rọc

Thr force to pull the object up in cases of Direction of the traction force intensity of the traction force Pulley not use From the bottom ...N Fixed pulley use .... Thr force to p

UNIT 16 PULLEYS

Usesing pulleys

A heavy concrete pipe rolled

down into a ditch How can

we raise it?

Some people decide to use a

pulleys to raise it Is it easier

to do like that?

UNIT 16 PULLEYS

I FIND OUT A PULLEY

Fixed pulley Movable pulley

Two types of pulley

+ Fixed pulley ( axle is fixed)

+ movable pulley ( axle is movable)

C1 Describe pulleys illustrated in this

figure?

UNIT 16 PULLEYS

I FIND OUT A PULLEY

Two types of pulley

+ Fixed pulley ( axle is fixed)

axle

rope

Grooved edge

The pulleys have to

How do pulleys help human work easier?

II HOW DO PULLEYS HELP HUMAN

BEING DO THEIR WORK MORE EASILY?

1 Experiment

a wheel,

a axle,

a rope and grooved edge.

a Experiment tools.

+ A dynamometer

+ A cylindrical metal bock ( an object)

+ A rack

+ A pulley

+ A rope

UNIT 16 PULLEYS

I FIND OUT A PULLEY

Two types of pulley

+ Fixed pulley ( axle is fixed)

+ movable pulley ( axle is movable)

The pulleys have to

II HOW DO PULLEYS HELP HUMAN

BEING DO THEIR WORK MORE EASILY?

1 Experiment

a wheel,

a axle,

a rope and grooved edge.

Thr force to pull the object up in cases of

Direction of the traction force

intensity of the traction force

Pulley not use From the bottom .N Fixed pulley

use

.

.N Movable

pulley use . N

UNIT 16 PULLEYS

I FIND OUT A PULLEY

Table 16.1 Results of the experiment

a Experiment tools.

+ A dynamometer

+ A cylindrical metal bock ( an object)

+ A rack

+ A pulley

+ A rope

Two types of pulley

+ Fixed pulley ( axle is fixed)

+ movable pulley ( axle is movable)

II HOW DO PULLEYS HELP HUMAN

BEING DO THEIR WORK MORE EASILY?

1 Experiment

b Conduct the measurement

UNIT 16 PULLEYS

I FIND OUT A PULLEY

II HOW DO PULLEYS HELP HUMAN

BEING DO THEIR WORK MORE EASILY?

1 Experiment

b Conduct the measurement

Thr force to pull the object up in cases of

Direction of the traction force

intensity of the traction force

Pulley not use From the bottom .N Fixed pulley

use

.

.N Movable

pulley use . N

Table 16.1 Results of the experiment

2

From the top

From the bottom 1

C2 we pull up the object in the verticai direction, reading dynamometer and write the traction force into table 16.1

C2 How direction pull the object

by fixed pulley in Fig 16.4?

C2 we pull the object by fixed pulley, reading dynamometer and write the traction force into table 16.1

C2 How direction pull the object

by movable pulley?

C2 we pull the object by movable pulley, reading dynamometer and write the traction force into table 16.1

UNIT 16 PULLEYS

I FIND OUT A PULLEY

II HOW DO PULLEYS HELP HUMAN

BEING DO THEIR WORK MORE EASILY?

1 Experiment

Thr force to pull the object up in cases of

Direction of the traction force

intensity of the traction force

Pulley not use From the bottom .N Fixed pulley

use

.

.N Movable

pulley use . N

Table 16.1 Results of the experiment

2

From the top

From the bottom 1

2 Comment

C3.a) compare Direction, intensity of the traction force to direction pull the object up and the traction force

through the fixed pulley.

C3.a) Direction, intensity of the traction

force to direction pull the object up and

the traction force through the fixed pulley

is oppersit, but intensity of the traction

force same

C3.a) compare Direction, intensity of the traction force to direction pull the object up and the traction force

through the movable pulley.

C3.a) Direction, intensity of the traction

force to direction pull the object up and

the traction force through the movable

pulley is same, but intensity of the

traction force ……

UNIT 16 PULLEYS

I FIND OUT A PULLEY

II HOW DO PULLEYS HELP HUMAN

BEING DO THEIR WORK MORE EASILY?

1 Experiment

2 Comment

3 conclusion

C4 Find the correct words to fill the blanks in

the following sentences:

a) ……… pulley has the effect of

change the direction of the traction force

over a direct traction force

b) ……… pulley has not the effect of

change the direction of the traction force

over a direct traction force but traction force

is less than the weight of the object

fixed movable

UNIT 16 PULLEYS

I FIND OUT A PULLEY