Bài 16. Ròng rọc

Trang 2

Usesing pulleysA 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

Trang 3

UNIT 16 PULLEYS

I FIND OUT A PULLEY

Fixed pulleyMovable pulley

Two types of pulley

+ Fixed pulley ( axle is fixed)

+ movable pulley ( axle is movable)

C1 Describe pulleys illustrated in this

Trang 4

UNIT 16 PULLEYS

I FIND OUT A PULLEYTwo types of pulley

+ Fixed pulley ( axle is fixed)

+ movable pulley ( axle is movable)wheel

axle

ropeGrooved edge

The pulleys have to

How do pulleys help human work easier?II HOW DO PULLEYS HELP HUMAN

Trang 5

a Experiment tools + A dynamometer + A cylindrical metal bock ( an object) + A rack + A pulley + A ropeUNIT 16 PULLEYS

I FIND OUT A PULLEYTwo types of pulley

+ Fixed pulley ( axle is fixed)

+ movable pulley ( axle is movable)The pulleys have to

II HOW DO PULLEYS HELP HUMAN

Trang 6

Thr force to pull the object up in cases ofDirection of the traction forceintensity of the traction forcePulley not useFrom the bottom .NFixed pulley use NMovable pulley use . NUNIT 16 PULLEYS

I FIND OUT A PULLEY

Table 16.1 Results of the experimenta 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

Trang 7

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 ofDirection of the traction forceintensity of the traction forcePulley not useFrom the bottom .NFixed pulley use NMovable pulley use . NTable 16.1 Results of the experiment2From 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

Trang 8

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 ofDirection of the traction forceintensity of the traction forcePulley not useFrom the bottom .NFixed pulley use NMovable pulley use . NTable 16.1 Results of the experiment2From the top From the bottom 12 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

Trang 9

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

Trang 10

UNIT 16 PULLEYS