mechanical systems study guide

supporting point of lever

output force, being moved or lifted

input force

fulcrum in the middle

load in the middle

• effort in the middle

• force advantage

• fulcrum is closer to load, meaning less effort is needed

• easier to lift load

• load moves slower

• harder to lift load

• load moves faster

• change the direction of force

• use gravity to help move load

• several pulleys reduce force to lift an object because spreads out weight

• force advantage

• more force

• heavier to lift

• less rope

• less force

• uses more rope

• multiple movable pulley and multiple single fixed pulley

• more rope

• pulled a farther distance

• load requires less force

• turn motion to force

• transfer energy

• driving gear (first one)

• force directed to driven gear (last one)

• follower gears are idler gears (middle ones)

more than two gears

• two gears working together

• on a track

two gears with teeth that fit into links of a chain

same direction

different direction

force advantage

speed advantage

force ratio

describes relationship between amount of output force to input force to move object over a distance

MA = FL/FE = load force (N) / effort force (N) = effort arm (M) / load arm

force advantage

• effort lower

• speed and distance sacrificed

no difference

• change in direction

speed advantage

• effort is greater

• load travels faster

• load travels further

Work = force x distance

light, hydro, kinetic, potential, etc.

energy switches to different type in same object

same type of energy moves from one object to another

• how much energy from machine was actually transferred to load

• stated as percent

• higher efficiency, better at transferring energy

• never a completely efficient machine because there is a loss of energy

adding lubricants (like grease) to reduce friction

efficiency = work output / work input x 100%

• decrease amount of effort or force needed

• increase distance object needs to move

• same amount of work being done, work is easier though

input work

output work

• amount of work stays the same

• energy lost

• ramp increases amount of overall distance

• ramp reduces force

• mass is amount of particles in an object

• weight is acceleration of gravity acting on mass

• 1.0kg = 9.81N

• made up of simple machines and subsystems

• function to describe what the overall system is designed to do

when two levers are joined to change direction of force to make objects move

changing one energy to another

difference between the speed of two gears