1. Machines

2. Machines and Work Machines make work easier to perform.
They do this by multiplying force, changing the distance the object moves or changing the direction of the force.
Ex. A wrench makes things tighter because it makes the force we add bigger.

3. Machines The force a machine exerts is called the output force.
The force you exert into the machine is called the input force.

4. Efficiency Efficiency compares the output to the input.
No machine is 100% efficient because of friction and other forms of wasted energy.
A theoretical machine with an efficiency of 100% is called an ideal machine.

5. The 6 Simple Machines
Lever, Pulley, Wheel and Axle, Inclined Plane, Screw & Wedge
Pulley and Wheel and axle are forms of the lever
Wedge and the screw are forms of the inclined plane

6. The Lever A rigid bar that turns around a point called a fulcrum.
Multiply the applied force.
Examples: Crowbar, Seesaw……

7. 3 Classes of levers
1st - changes the direction of the force. The fulcrum is in the middle.
2nd - increases the force but does not change the direction of the force. Fulcrum at the end.
3rd - increases the distance and does not change the direction of the force. Fulcrum at the end.

8. The Pulley Form of the lever
Can change the direction of force or decrease the force needed to move a heavy object.
Example: to hoist an engine out of a car.

9. The Wheel and Axle Modified Lever.
Large wheel with an axle at its center.
The outer wheel turns with less force and then turns the axle.
Examples: Steering Wheel, Door Knobs

10. The Inclined Plane A flat surface with one end higher than the other.
Decreases force needed and increase distance that force is applied.
Examples: Wheel chair Ramp, truck ramp

11. The Wedge A double sided incline plane.
Force is applied by driving the wedge into something.
Examples: Knife, Ax, Nail

12. The Screw An inclined plane wrapped around a wedge or cylinder.
A circular force is applied to overcome the resistance.
Examples: Screw, Bolt, Car Jack

13. Complex or Compound Machines
Anything that contains two or more simple machines is complex.
Efficiency of these machines is never 100%
Energy may be lost to heat and thus wasted.