7. Machines do 3 things…
Multiplies Multiplies Changes
Force Distance Direction
• Makes work • Makes work • Makes work
easier when easier by easier by
force is multiplying the changing the
multiplied distance over direction in
which you exert which force is
force exerted
11. Actual or Ideal?
• Mechanical advantage that a machine
provides in a real situation is called the actual
mechanical advantage
• The mechanical advantage of a machine
without friction is called the machine’s ideal
mechanical advantage
16. 3 Types of Levers
• First‐class: seesaw, scissors, pliers – fulcrum in
between input and output force
• Second‐class: door, wheel barrow, bottle
opener – output force greater than input force
• Third‐class: baseball bat, shovel, rake – output
force less than input force
• Ideal Mechanical Advantage=
Distance from fulcrum to input force/
distance from fulcrum to output force
18. 6. Pulley
• A grooved wheel with a rope (or chain, or
even a steel cable) wrapped around it.
• Fixed pulleys change direction of input force
but not the amount of force applied
• A moveable pulley has an ideal mechanical
advantage of 2