Chapter 5 - Work and Machines
Order by
59 terms
Terms | Definitions |
|---|---|
 work | the product of force and distance when force is used to move an object |
| joule | unit of work, the SI unit of energy |
| machine | a device that changes the amount of force exerted or the direction in which force is exerted |
| input force | the force exerted on a machine |
| output force | the force applied by a machine |
| mechanical advantage | the number of times the force exerted on a machine is multiplied by the machine |
| efficiency | the percentage of the input work that is converted to output work |
| actual mechanical advantage | the mechanical advantage that a machine provides in a real situation |
| ideal mechanical advantage | the mechanical advantage that a machine would have without friction |
| inclined plane | a simple machine consisting of a flat surface with one end higher than the other |
| wedge | a simple machine consisting of a device that is thick at one end and tapers to a thin edge at the other |
| screw | a simple machine that consists of an inclined plane wrapped around a central cylinder to form a spiral |
| lever | a simple machine consisting of a rigid object that pivots about a fixed point |
| fulcrum | the fixed point around which a lever pivots |
| wheel and axle | a simple machine consisting of two circular objects that are fastened together and rotate about a common axis |
| pulley | a simple machine consisting of a grooved wheel around which is wrapped a rope, chain, or cable |
| compound machine | a device that combines two or more simple machines |
| gears | two or more wheels linked together by interlocking teeth |
| ideal machine | machine with no friction W(in)=W(out) |
| Simple machines do not multiply energy | W(out) is never > W(in) |
| A watt is equal to __________ | one newton per second |
| Work | A transfer of energy when a force makes an object move in the same direction (Joules) |
| Power | The rate or amount of work being done in one second (Watts) |
| mechanical advantage | how many times a machine multiplies a force |
| efficency | input compared to output |
| simple machine | machine that has only 1 movment |
| compound machine | combination of simple machines |
| The Force-Distance Trade-off | Machines often will increase the distance of the object has to move, but the input effort force is decreased. The same amount of work is done. |
| Effort force | the force applied to a machine |
| Resistance force | the force applied by the machine to overcome resistance is called |
| Input work | work done by you on the machine |
| Output work | work done by the machine |
| The Ideal Machine | Input work = Output work (not possible due to friction) |
| Mechanical advantage | the number of times a machine multiplies the effort force |
| less than one | When MA is ____ ____ ___, the machine increases the distance moved or the speed |
| equals one | When the MA is ______ ___, the machine changes the direction of the Fe. |
| greater than one | When the MA is _______ ____ ___, the machine increases the Fe. |
| High efficiency machines | produce less heat from friction |
| Efficiency | W out / W in x 100% |
| oil grease | You can make machines more efficient with ___ ______. |
| Simple machine | a machine that does work with only one movement |
| Levers | barsthat are free to pivot or turn about a fixed point called a fulcrum |
| resistance arm | the distance from the fulcrum to where the resistance force is applied |
| half | When you double the distance, you can ____ the force |
| effort arm | the distance from the fulcrum to where the effort force is applied |
| first class lever | used to multiply the force and change the direction of the applied force (screwdriver opening a paint can) |
| second class lever | the resistance froce is located between the effort force and the fulcrum; multiplies force (wheelbarrow) |
| IMA | the length of the arm / length of the resistance arm |
| pulley | a grooved wheel with a rope, chain, or cable running along the groove |
| fixed pulley | a modified first class lever that can multiply force and/or change the direction of the applied force; attatched to something that does not move |
| moveable pulley | one end of the rope is fixed and the wheel is free to move; it multiplies force by increasing the distance you pull |
| block and tackle pulley | a system of pulleys made of fixed and moveable pulleys; can have large mechanical advantages |
| wheel and axle | a machine made up of two wheels of different sizes that rotate together (doorknoibs, pencil sharpener) |
| larger wheel | the effort force is usually exerted on the |
| resistance force | the smaller wheel is the |
| gears | two or more interlocking wheels that may change the direction of the force |
| inclined planes | sloping surfaces that reduce the amount of force required to do work by increasing the distance over which the force is applied |
| length of slope / height of slope | For inclined planes, the IMA = |
| less force | As a ramp/inclined plane is made longer and less steep, ____ _____ is required. |
First Time Here?
Welcome to Quizlet, a fun, free place to study. Try these flashcards, find others to study, or make your own.