Bài 16. Ròng rọc

UNIT 16. 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?
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?
I. FIND OUT A PULLEY
I. FIND OUT A PULLEY
Two types of pulley
+ Fixed pulley ( axle is fixed)
+ movable pulley ( axle is movable)
wheel
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.
Experiment tools.
+ A dynamometer
+ A cylindrical metal bock ( an object)
+ A rack
+ A pulley
+ A rope
I. FIND OUT A PULLEY
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.
I. FIND OUT A PULLEY
Table 16.1. Results of the experiment
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.
I. FIND OUT A PULLEY
II. HOW DO PULLEYS HELP HUMAN BEING DO THEIR WORK MORE EASILY?
1. Experiment.
b. Conduct the measurement.
Table 16.1. Results of the experiment
2
From the top.
From the
bottom.
1
I. FIND OUT A PULLEY
II. HOW DO PULLEYS HELP HUMAN BEING DO THEIR WORK MORE EASILY?
1. Experiment.
Table 16.1. Results of the experiment
2
From the top.
From the
bottom.
1
2. Comment.
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) 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 ……
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:
………………..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
I. FIND OUT A PULLEY