Simple machines: Levers
Levers have a simple (1)______________ that moves on a (2)______________.
The lever transmits a (3)______________ which makes easier to lift a (4)__________________.
1. A rigid bar
2. Pivot
3. Force
4. Load
A ____________ can help us lift objects more easily, by changing the direction of the force, meanwhile the _______________ or the ___________ are the same.
A pulley can help us lift objects more easily, by changing the direction of the force, meanwhile the force or the load are the same.
Mechanical components are __________ machines that transmit _____________.
Simple
Movement
Who said... “Give me a lever and a place to stand and I will move the Earth”
Archimedes
If we wrap an inclined plane around a cylinder we make a __________
Screw
Lever class?
The LOAD is between the PIVOT and the FORCE. It is useful for opening bottles.
Class 2 lever.
The_________________ lets us move objects using less force, without changing direction.
The inclined plane lets us move objects using less force.
The _____________ is a bent lever that transmits its movement and axle.
Example ________________
Crank
Pedals of a bike
For what did the people use the screw of Archimedes?
To raise water an irrigate crops
Throw join inclined planes.
Lever class?
The PIVOT is between the LOAD and the FORCE. It is useful to weight things.
Class 1 lever
When a ramp is ___________________ we need to use less force but the ramp is ________________.
Less steep
longer.
Gears are several ___________ that are connecte. They transmit movement from one _________ to another and __________________the ___________ of the movement.
Example: Gears in______________
Cog
Cog
change the direction
Clock
What is the machine that Archimedes invented to defend his native city?
The claw
Give an example of:
Cogs and a chain
Rack and cog
Gears
Cogs and a chain: Pedals
Rack and cog: Corkscrew
Gears: clock engine
Lever class?
The FORCE is between the PIVOT and the LOAD. It is useful for cleaning the floor.
Class 3 lever
Three examples that use inclined planes.
Ramp
Screw
Wedge
Explain how work cogs and chain.
When we turn one cog it transmits movement to the other cog thanks to the chain. Both cogs move in the same direction. We use this in bicycles and motorbikes.
How does it work the claw of Archimedes?
It consisted of a beam with a hook hanging from one end. On the other end, ther was a system of pulleys. People or animals pulled the ropes of the pulley and lifted the enemy ships. Then they dropped the ships into the water, sinking them.
Explain two complex mechanism of a bike
The back wheel receives force from the pedals.
Break handles are levers.
The handlebars control the direction of the front wheel.
The pedals are cranks.
The wheels turn on an axel.
Draw a mock of each class of lever.
Lever 1: force- pivot- load
Lever 2: pivot- load - force
Lever 3: pivot- force- load
If I have 2 wheels to lift a load of 120 kg, I only need a force of ____________
If I add 2 more wheels to lift the same load (120 kg), I only need a force of ______________.
60 kg force
30 kg force
Explain the mechanism of a rack and cog and where we can find this complex machine.
When the cogs turns, the rack moves in straight line. We use this mechanism in corkscrews, and sliding doors.
Isaac Newton
What does the Law of Universal Gravitation say?
Any two bodies in the universe attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them