PHYSICS - SIMPLE MACHINES QUIZ

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SIMPLE MACHINES QUIZ

PHYSICS - LEVER CLASSES #3

CLASS 3 LEVER






CLASS ONE LEVER




CLASS TWO LEVER

PHYSICS - SIMPLE MACHINES - ACTIVITIES #2

SIMPLE MACHINES

LEVERS

PHYSICS - SIMPLE MACHINES REVIEW

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STUDY JAMS - SIMPLE MACHINES

SIMPLE MACHINE - MATCHING

Simple Machines

More educational videos on Simple Machines at NeoK12.com  

 Simple machines are tools that make work easier.  They have few or no moving parts.  These machines use energy to work.  

Compound machines have two or more simple machines working together to make work easier.

In science, work is defined as a force acting on an object to move it across a distance. 

• Pushing, pulling, and lifting are common forms of work. Furniture movers do work when they move boxes. Gardeners do work when they pull weeds. Children do work when they go up and down on a see-saw. Machines make their work easier. The furniture movers use a ramp to slide boxes into a truck. The gardeners use a hand shovel to help break through the weeds. The children use a see-saw to go up and down. The ramp, the shovel, and the see-saw are simple machines.

Lever
Inclined Plane
Wheel and Axle
Screw
Wedge
Pulley

SIMPLE MACHINES - QUIZ

PHYSICS - LEVERS REVIEW

Remember:  

There are 3 kinds of Levers.  Every kind of Lever has:

• a balance point (fulcrum)
• a point where the weight is
• a point where force is applied

Add these study questions in your notes as well as the following information on Levers.

LEVERS

Questions For Study

1. Why is energy needed?
Energy is needed to do work.

2. How do scientists define “work”?
Work occurs when a force moves an object.

3. What is the difference between class 1, class 2, and class 3 levers?
A class-1 lever has the fulcrum located somewhere between the effort and the load. With this kind of lever, the direction of force is changes. Effort applied downward moves the load up. Effort applied upward moves the load down.



A class-2 lever has its fulcrum at one end of a lever arm. The load is between the fulcrum and the effort. With this kind of lever, the direction of effort is not changed. Pushing up on the class-2 lever arm pushes up on the load. Pushing down on the lever arm pushes down on the load. To gain a mechanical advantage, the load is places closer to the fulcrum than to the effort. The class-2 lever always reduces effort.



In a class-3 lever, the fulcrum is at one end, and the effort is applied between the fulcrum and the load. With this kind of lever, the direction of effort is not changed. The load moves in the same direction as the effort. The gain offered by a class-3 lever is one of distance.


4. Explain why a simple machine makes work easier to do but does not save energy.Most simple machines do not save energy. They distribute the force needed to do work over a longer distance.

Generally, simple machines can help us in two ways. We can apply less effort over a greater distance, or we can apply more effort over a shorter distance. Simple machines provide a gain in effort or a gain in distance. In addition, some simple machines change the direction of effort.

5. How does a lever or pulley give you mechanical advantage?Sometimes we may want to lift, push, or pull an objects, or we may need to break or cut them. Some of these jobs require a lot of force. When we use simple machines, we gain a mechanical advantage by increasing the amount of force we can bring to bear on an object.

6. What is friction? When is it necessary to reduce friction?Friction is a force that slows down or stops motion. There is friction when two parts of a machine rub against each other.

One way to reduce friction is by covering surfaces that rub together with grease or oil. Another way is by using wheels.

7. What is the difference between a fixed and a movable pulley?A fixed pulley can change the direction of your force. You pull down on one end of the rope. The load is pulled up by the other end. It takes the same force to lift a load with a fixed pulley as it does without a fixed pulley.

A movable pulley does not change the direction of your force. Like a lever, a movable pulley lets you use less force to lift a load. But you must pull the rope a longer distance than the load moves. The smaller force needed to lift a load with a movable pulley is used over a longer distance. So a movable pulley does not save energy.

8. Where in real life can you find levers and pulleys?

• Examples of class-1 levers are: a seesaw, claw hammer, crowbar, scissors, pliers, and tin snips.

• Examples of class-2 levers are: a wheelbarrow, paper cutter, door, nutcracker, garlic press, bellows, and a bottle opener.

• Examples of class-3 levers are: a fishing pole, hammer, baseball bat, hockey stick, golf club, tennis racket, shovel, pitchfork, hoe, broom, tweezers, ice tongs, and your arms and legs.

• Pulleys are used to lift items from one level to another. 
• Pulleys can be fixed or movable or combinations of both.
•  Pulleys are used in block and tackles, large cranes, chain hoists, and hydraulic systems.

9.  TYPES OF LEVERS:

Levers are simple machines that have a rigid arm around a fixed point or fulcrum. 

Force is transferred from one part of the arm to another. 

• The input (effort) force is multiplied or redirected into anoutput (resistance) force. 
• Levers are divided into three different classes. 
• A first-class lever has the fulcrum between the input and output forces. 

A Type 1 Lever.

 In a Type 1 Lever, the pivot (fulcrum)  is between the effort and the load. In  an off-center type one lever (like a  pliers), the load is larger than the  effort, but is moved through a smaller  distance.

Examples of common tools (and other items) that use a 

Type 1 lever include:

Item		Number of Class 1 Levers Used
see-saw		a single class 1 lever
hammer's claws		a single class 1 lever
scissors		2 class 1 levers
pliers		2 class 1 levers

A SECOND-CLASS LEVER has the output force between the fulcrum and the input force. 

A Type 2 Lever.

In a Type 2 Lever, the load is between the pivot (fulcrum) and the effort.

Examples of common tools that use a type 2 lever include:

Item		Number of Class 2 Levers Used
stapler		a single class 2 lever
bottle opener		a single class 2 lever
wheelbarrow		a single class 2 lever
nail clippers		Two class 2 levers
nut cracker		Two class 2 levers

The third-class lever has the input force between the fulcrum and the output force. 

A Type 3 Lever.

 In a Type 3 Lever, the effort is  between the pivot (fulcrum) and the  load.

Examples of common tools that use a type 3 lever include:

Item		Number of Class 3 Levers Used
fishing rod		a single class 3 lever
tweezers		Two class 3 levers
tongs		Two class 3 levers

Different types of LEVERS into their appropriate classes.

 LABEL THE DIAGRAM

PHYSICS - SIMPLE MACHINES - II

Lever

     A lever is a simple machine made with a straight bar that moves on a fixed point called a fulcrum.  All levers have two parts, the bar and the fulcrum.  The longer the lever is, the less force will be needed to move the load. 

     The load and the force move in opposite directions.  Notice that as the hammer is pulled down, the nail moves up.

Examples of Levers
The tab is a lever used to open the can.	The screwdriver is being used as a lever.	The handle on the pump is a lever.
The can opener is a lever.	The bottle opener is a lever.	The shovel is a lever.

Wheel and Axle

     A wheel and axle is made from a wheel that turns on a center post.  The larger the wheel is, the less force will be needed to move the load.  There are two parts to this simple machine, the wheel and the center post called the axle.

     The force moves in the same direction as the load.  Notice that in the picture, the force pushes in the same direction that the skateboard is moving.

Examples of Wheel and Axles
Skates use wheel and axles.	We use a wheel and axle to reel in the fishing line.	Wheelchairs use wheel and axles.
The knob part is the wheel.  The axle connects the two knobs.	The steering wheel is a wheel and the axle goes into the steering column.	Skateboards use wheel and axles.

Inclined Plane

     Any slanted surface is an inclined plane.  A ramp is the most common type.  A ramp is higher at one end than at the other.  The longer the inclined plane is, the less force will be needed to move the load.  The only part of an inclined plane is the slanted surface.  

     The load and the force move in the same direction.  Notice in the picture that the force is pushing the lawn mower in the same direction it is moving.

Examples of Inclined Planes
An inclined plane lifts the front of this car.	A long inclined plane equals the four steps.  The ramp goes up, turns and continues.		A short ramp is needed to equal these two steps.
Inclined planes make our work easier.		An inclined plane is used to lift this heavy wheelbarrow into this trailer.

Wedge

A wedge is made by putting two inclined planes together.  They come together to form a V-shape.  A wedge may be used to lift or pry apart heavy objects.  A wedge can also be used to stop an object from moving.   A wedge has only one part.       The force and the load move in different directions.  In this picture, as the force moves the ax down, the load (wood) breaks apart and falls to the sides.

Examples of Wedges
The blade of a knife is a wedge.	Each blade of the scissors is a wedge.	The sharp edge of an ax is a wedge.
The sharp edge of the shovel is a wedge.	A door stop is a wedge that stops the door from moving.	A wedge called a chock stops the car from moving.

Pulley

     A pulley is a wheel with a rope around it.  The rope fits into the groove on the wheel.  The larger the wheel is, the less force will be needed to move the load.  There are two parts to a pulley, the wheel and the rope. 

     The load and the force move in opposite directions.  As the rope is pulled down, the flag goes up.

Examples of Pulleys
Pulleys are used to open and close curtains and blinds.	A pulley is used to make this ladder longer.	A pulley is a grooved wheel with a rope around it.
Pulleys are used for exercise, especially in hospitals, to help patients grow stronger.	Pulleys are used to raise and lower sails on sailboats.	Pulleys are used to raise and lower flags.

Screw

     A screw is an inclined plane that is wrapped around a center post.  The longer the inclined plane is the closer the threads of the screw will be and the less force will be needed to move the load.  A screw has two parts, the inclined plane and the center post. 

     The force and the load move in the same direction.  As the force pushes down on the screw, the screw goes down into the wood.

Examples of Screws

Some screws have a sharp point and are mostly used on wood.
The faucet has threads to screw the hose on.
Some screws have a flat end.  We call these screws bolts.   Most bolts use a nut.

Many bottles and jars have screw on lids.

Bicycle tires have threads on the stem to screw the cap on.
Light bulbs have threads to screw them into sockets.

INVENTION AT PLAY

MORE EXAMPLES OF SIMPLE MACHINES

Add 3 or more simple machines in your notes from this module

draw, label & explain.  Use color!

DUE:  Wednesday 10/3