Simple Machines

What do simple machines generally do?

generally, the six simple machines reduce required effort by minimizing friction or spreading effort over greater distance and time

changes the magnitude or direction of a force

What is mechanical advantage also called? What is it?

leverage; the ratio of the output to the input force

A mechanical advantage results in…

less force applied over a greater distance

Inclined Plane

• flat surface whose endpoints are at different heights, resulting in a slope

• amount of force to move an object is reduced, but the distance is increased

• ie a ramp

wheel and axle

• reduce friction of item (ie a truck with wheels) traveling across the ground

Lever

• a rigid object that is used with an appropriate fulcrum or pivot point to multiply the mechanical force that can be applied to another object

• also termed mechanical advantage

• a wheelbarrow is a type of lever, the wheel works as the fulcrum

• scissors are a type of lever, the fulcrum is where the blades cross

Pulley (Block)

• used to change the direction of an applied force, transmit rotational motion, or realize a mechanical advantage

• a pulley helps an individual lift an object by spreading the weight of the object over the length of the rope

What is the wheel of a pulley called?

a sheave

Wedge

• variation of the inclined plane

• push wedge in object to push them apart

Screw

• all screws are inclined planes

• a screw can convert a rotational force (torque) to a linear force, and vice versa

• as the screw rotates outwards, the weight rises

• as the screw rotates inwards, the weight lowers