1. Machines Review and summary of important topics

2. Table of Contents  Work, Power & Force Work, Power & Force  Simple Machines Simple Machines  Types of Simple Machines Types of Simple Machines  Compound Machines Compound Machines  Mechanical Advantage Mechanical Advantage  Efficiency Efficiency

3. Work, Power & Force  Work: Transfer of energy from one object to another by force  Measured in JOULES  W = F x d  Power: Rate at which work is done  Measured in WATTS  P = W/t

4. Simple Machines  A simple machine does work using only one movement  What are the 3 ways in which machines can help you do work?  Change the distance at which the force is applied  Change the direction of the force  Change the size of the force

5. Types of Simple Machines  Inclined Plane Inclined Plane  Screw Screw  Wedge Wedge  Pulley Pulley  Wheel & Axle Wheel & Axle  Levers Levers

6. Inclined Plane  A flat, sloped surface  ie: slide, ramp, stairs Screw  An inclined plane wrapped around a cylinder Wedge  A sloped surface that moves

7. Pulley  A grooved wheel with a rope/wire wrapped around it  The wheel is attached to a fixed, unmovable surface  The wheel is attached to the object being lifted/moved Fixed Pulley Movable Pulley

8. Wheel & Axle  An axle (rod) attached to the center of a wheel

9. Classes of Levers  1 st Class: Fulcrum is between the input and output force  2 nd Class: Output force is between the input force and fulcrum  3rd Class: Input force is between the output force and fulcrum  Ideal Mechanical Advantage of a Lever

10. Compound Machine  2 or more simple machines combined to perform a function  ie: a gear  Wedges  Wheel and axle  Lever

11. Mechanical Advantage  Ratio of a machine’s output force to its input force  No units MA = Output force/input force MA = F out / F in  Ideal mechanical advantage Ideal mechanical advantage

12. IMA – Ideal Mechanical Advantage  Ideal mechanical advantage is the mechanical advantage of a simple machine when friction is not present.  The operation of a machine at its IMA is impossible because friction is always present. IMA of a Lever = length of input arm length of output arm

13. Efficiency  Ratio of output work to input work  Calculated as a percent ratio Efficiency = Output work/input work x 100%