1. Machines

2. Machines Machines are devices that make work easier.
Machines make work easier by decreasing or redirecting the force applied.
Machines do not reduce the amount of work; they decrease the amount of effort needed.

4. Lever
A bar that is free to pivot around a fixed point or fulcrum.

5. Pulleys
A grooved wheel with a rope, chain or cable that changes the direction of the force.

6. Wheel and axle
A shaft attached to a large wheel that rotates together.

7. Inclined Plane or Ramp
A sloping surface that reduces the amount of force required to raise an object.

8. Wedge
A movable inclined plane that changes the direction of the force.

9. Screw
An inclined plane wrapped around a cylindrical post.

10. Complex machine A machine made of more than one simple machine.
Can you list the types of simple machines used in this bike?
Wheel & Axle
Lever
Screw
Pulley

11. Mechanical Advantage (MA)
The amount of times a machine multiplies your effort.
To calculate the MA of a lever divide the length of the force arm by the resistance arm.

12. Example of Mechanical Advantage of a Lever
MA = FA / RA
FA is the distance from the input force to the fulcrum.
RA is the distance from the resistance to the fulcrum.
FA = 36 inches
RA = 6 inches
MA = 6

13. Mechanical Advantage of Inclined Planes
To calculate the Mechanical Advantage of an inclined plane divide the length of the ramp by its height.
MA = L / H
L = length of ramp
H = height of ramp

14. Example of Mechanical Advantage of an Inclined Plane
Length = 8 feet
Height = 2 feet
What is the mechanical advantage?
MA = 4