Real World Simple Machines

ByProfessor D.M. Isaacson I

Lever

• rigid object and a fulcrum (or pivot)

• Applying a force to one end of the rigid object causes it to pivot about the fulcrum.

• Magnifies of the force at another point along the rigid object.

Here the crane operator uses the levers of the machine to operate the much larger arm,

Wheel & Axle • circular device that is attached

to a rigid bar in its center. • force applied to the wheel

causes the axle to rotate, which can be used to magnify the force – For example, having a rope

wind around the axle.

• force applied to provide rotation on the axle translates into rotation of the wheel– A lever that rotates around a

center fulcrum… In the coreless impact drill, a ‘large’ gear is driven which rotates the axle-in this case, the chuck

Inclined Plane

• a plane surface set at an angle to another surface.

• do the same amount of work by applying the force over a longer distance.

Because the ladder is a shorter distance, it is more difficult to climb, compare to a stairway with a much longer distance, much easier to climb.

Wedge

• a double-inclined plane that moves to exert a force along the lengths of the sides.

• The force is perpendicular to the inclined surfaces, so it pushes two objects (or pieces of a single object) apart. The splitting maul uses the basic concept

of the wedge to split firewood much more easily than with a smaller axe.

Screw

• a shaft that has a in inclined groove along its surface.

• rotate the screw– the force is applied

perpendicular to the groove, thus translating a rotational force into a linear one.

The blades of the ice auger cut, as the auger portion draws the whole tool down into the ice.

Pulley

• a wheel with a groove along its edge, where a rope or cable can be placed.

• applies force over a longer distance, and also the tension in the rope or cable, to reduce the magnitude of the necessary force. The old-fashioned version of the wire stretcher

utilized twp pulleys and a length of rope to greatly reduce the work involved with tightening a wire fence.