The structure and the importance of the levers
The levers are the most common simple machines which they help man to perform heavy tasks easily . They were first described in 260 B.C , The liver is affected by an effort force and a resistance force , and It is a rigid bar ( straight or curved ) that rotate around a fixed point called fulcrum .
The liver consists of :
A resistance force which is the force that resulted from the weight of the body that we want to move .
An effort force which is the force that exerted by a person to equilibrate the resistance .
The fulcrum which is a fixed point , where the bar rotates around .
The lever consists of a resistance force , an effort force and fulcrum .
Examples on levers
Stapler , Manual broom , Crowbar , Seesaw , Scissors , Bottle opener , Nutcracker , Ice or sweet holder and Wheelbarrow .
The importance of levers
The levers increase the force because they save the exerted effort by using the small force to make the great effort as moving the heavy load .
Examples : crowbar , bottle ( soda water ) opener , nutcracker and wheel barrow .
They increase the distance , where some levers allow the exerting force for a small distance to move an object for a longer distance .
Examples : The manual broom , If your hand moves a small distance at the upper part of the manual broom , the lower part will move a longer distance .
- They avoid dangers as they are used to pick up the hot , cold and poisonous materials . Examples : Ice holder and coal holder ( coal tongs ) .
They increase the speed of the objects that we affect on
Examples : Hockey bat .
They move the force from one place to another .
Examples : The force of your hand on the manual broom moves from one place to another to collect the garbage without bending .
They have the accuracy in performance as they are used to pick up very small object .
Example : Tweezers .