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the first lesson in the second term types of levers

ابن عز: عدد المساهمات : 194
نقاط : 244
تاريخ التسجيل : 2009-07-11
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الموقع : نائب رائيس الموقع

Post n°1

Re: the first lesson in the second term types of levers

Post ابن عز Fri 25 Feb 2011, 10:47 am

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BESHOY

BESHOY: عدد المساهمات : 15
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Post n°2

the first lesson in the second term types of levers

Post BESHOY Sun 20 Feb 2011, 7:53 pm

types of levers

How to Identify Three Types of Levers

Levers are one of the basic simple machines, along with wedges, pulleys, screws, inclined planes and the wheel and axle. Every gadget or machine around us is made up of one or more of these simple machines.
.Difficulty: Moderate
Instructions.1
A lever is a rigid bar that pivots at a point called the "fulcrum" and is used to move things. The fulcrum can be anywhere along the lever. The thing that you are moving is called the "load," and the force applied on the lever is simple referred to as the "force." A seesaw is a good example of a lever that has the fulcrum in the middle. The riders take turns being the load or the force, depending upon whether they are pushing up or gliding down.

2
You will need to know the three types of levers. They are called first, second, and third class levers. First class levers have the fulcrum in the middle, as in a seesaw. Second class levers have the fulcrum at one end, the force at the other end and the load in the middle. A good example of a second class lever is a wheelbarrow. Third class levers have the fulcrum at one end and the load at the other end, with the force in the middle. A baseball bat is a good example of a third class lever.

3
The first step to identifying which kind of lever you are looking at is to notice where the fulcrum is. If the fulcrum is somewhere in the middle, it's a first class lever. The fulcrum can be fairly near to one end and still be considered in the middle, if the force and the load are on opposite sides of the fulcrum. For example, a paint can opener is still a first class lever even though the pivot point is very near the end, right on the edge of the can. The force is your hand moving it down, and the lid is the load you are moving, and these are on opposite sides of the pivot point. Other examples of first class levers include a car jack, a pry bar, an old-fashioned balance scale, and a simple catapult. A pair of scissors is actually two first class levers working together.

4
If your lever isn't a first class lever, you must determine whether it is second or third class. Both of these types of levers have the fulcrum all the way at one end. The difference is where the load is and where the force is being applied. Third class levers are easier to spot than second class, because the load is often a conspicuous object such as a ball, a fly or a nail (being hit by a bat, a swatter and a hammer, respectively). Most of the time, if there is an object being hit, you have a third class lever. If the lever is not third class, then it must be second class. Examples of second class levers are wheelbarrows and nut crackers.

5
Use a mnemonic to help you keep the levers straight. Here are some examples: "In a first class lever, the fulcrum's in the middle. If I seesaw with you, you seem to weigh little." This helps you to remember that a first class lever has the fulcrum in the middle, like a seesaw. "If you want some speed to swat or bat, a third class lever is where it's at!" This helps you to associate third class levers with things like bats and hammers. Check the Resources list below for an entire song about the types of levers.
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Read more: How to Identify Three Types of Levers | eHow.com http://www.ehow.com/how_2174950_identify-three-types-levers.html#ixzz1EXPYuFoy
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the first lesson in the second term types of levers

Re: the first lesson in the second term types of levers

the first lesson in the second term types of levers

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