Definitions

Systems - a group of parts that work together to perform a specific task


Physical system - a group of physical parts that work together to perform a specific task


Social system - a group of people, or other organisms, joining together to perform tasks and establish relationships


Force - any push or pull


Input - the force, energy, or raw materials that you put into a system 


Output - the task or service that a system performs


side effects - the unintended or undesired outputs of a system


systems thinking - taking into consideration the inputs, outputs, and side effects of systems


Simple machine - a device that requires a single force to work made up of one or 2 parts


Fulcrum - the pivot point of a lever 


load arm - the part of a lever that extends from the fulcrum to the mass being moved


effort arm - the part of a lever that extends from the fulcrum to where the force is applied


input force - the effort force applied to the lever 


output force - the force the lever applies to the load 


load force - the force that the input force has to overcome in order to cause movement


For each of the following simple machines, state the purpose of each:


  • Inclined plane -  a tilted, flat surface.

  • Wedge - a modified inclined plane that can be moved back and forth with ease.

  • Screw - is a device used in many cultures to lift water.

  • Lever -the force applied to one part of the lever can be changed or redirected in order to move a load.

  • Wheel + axel - the axle changes a small input force into a larger output force.

  • Pulley - used to help lift heavy loads or change the direction of a force.

  • Gear - They are used to speed up or slow down motion, or to change the direction of motion

magnitude: the quantity of force


Direction - refers to which way the force is pulling or pushing.


Newton: the unit used to measure forces (N)


Weight - the force of gravity acting on an object


Mass - the amount of matter that makes up an object or substance 


friction: the force that resists the movement of objects sliding or rolling over one another


static friction: the force that holds a motionless object where it is, preventing it from being moved across another object's surface


sliding friction: the force that acts like a brake when one surface slides over another surface


lubricant: a substance that reduces friction and causes surfaces to slide more easily


mechanical advantage: the ratio of output force to input force for a given machine


ideal mechanical advantage: the mechanical advantage of a machine if all of the input force is converted into output force; never possible in real-world applications

actual mechanical advantage: the mechanical advantage of a machine in real-world applications; equal to ideal mechanical advantage minus force lost to friction, slippage, and distortion