General+concepts+i.e+Levers+Gears,+Belts,+Pulleys+&+Inclined+Plane

Typ =General Concepts=

10.1.1 Define mechanical advantage, velocity ratio and efficiency.
Mechanical advantage //This is the factor that the machine multiplies the force put into it//Velocity ratio //A measurement of force amplification//Efficiency //Mechanical efficiency is the effectiveness of a simple machine// Society of Robots website.

10.1.2 Calculate mechanical advantage (MA), velocity ratio (VR) and efficiency for simple mechanical systems.
//MA = load/effort// //VR = distance moved by effort/distance moved by load// //Efficiency = MA/VR//

10.1.3 Describe first-, second- and third-class levers.
//Identify load (L), effort (E) and fulcrum (F) in first-class levers (E–F–L, for example, see-saw, crowbar, scissors), second-class levers (E–L–F, for example, wheelbarrow, bottle opener, nutcracker) and third-class levers (L–E–F, for example, tweezers, broom, fishing rod).//
 * Professor Breakers' learning labs on levers and simple machines.
 * The internet encyclopaedia of science.
 * PBS activity.


 * [[image:http://www.cagle.com/artists/Lester/LesterSamples/seesaw-01.jpg width="200" link="@http://www.cagle.com/artists/Lester/LesterSamples/seesaw-01.jpg"]] || [[image:http://mystagedlife.com/wp-content/uploads/2007/09/nutcracker.jpg width="200" link="@http://mystagedlife.com/wp-content/uploads/2007/09/nutcracker.jpg"]] || [[image:http://www.naturalhealthanswers.co.uk/UserFiles/551338_tweezers_2%20%20sxc.jpg width="200" link="@http://www.naturalhealthanswers.co.uk/UserFiles/551338_tweezers_2%20%20sxc.jpg"]] ||
 * 1st || 2nd || 3rd ||

10.1.4 Discuss the relevant efficiencies of the three classes of lever.
Class 1 & 2 levers are common as they provide a good mechanical advantage, on the other hand class 3 levers provide a MA near or below one.
 * Lever efficiency

10.1.5 Explain that, when a lever is in equilibrium, the net moment is zero.
When there is more than one force acting on a lever there will be more than one moment and a net moment can be calculated. If the the lever is not in motion i.e. in equilibrium then the net moment will be zero. In a see-saw the moments (turning affect) at the fulcrum will be clockwise as well as anti-clockwise, therefore when a see-saw is balanced then it is said to be in equilibrium and the moments will be zero.

10.1.6 Calculate mechanical advantage and effort for first-, second- and third-class levers.

 * Sample calculations

10.1.7 Describe gear systems.

 * HowStuffWorks on gears.
 * A Gear retailer has some good images.

10.1.8 Calculate velocity ratio for gear systems.

 * Technology Student has an explanation and some examples.


 * [[image:http://www.technologystudent.com/images2/cycle3.gif link="@http://www.technologystudent.com/images2/cycle3.gif"]] ||
 * [[image:http://www.technologystudent.com/images2/cycle5.gif link="@http://www.technologystudent.com/images2/cycle5.gif"]] ||

10.1.9 Describe the function of different types of gears in a range of objects.
//Use rack-and-pinion, bevel and worm gears.//
 * [[image:http://www.atlantadrives.com/splitpinion.jpg width="200" link="@http://www.atlantadrives.com/splitpinion.jpg"]] || [[image:http://www.indiamart.com/starenterprise/pcat-gifs/products-small/spiral-bevel-gears.jpg width="200" link="@http://www.indiamart.com/starenterprise/pcat-gifs/products-small/spiral-bevel-gears.jpg"]] || [[image:http://static.howstuffworks.com/gif/gear-worm.jpg width="200" link="@http://static.howstuffworks.com/gif/gear-worm.jpg"]] ||
 * [[image:http://www.carx.com/Portals/0/images/RackandPinion.jpg width="200" link="@http://www.carx.com/Portals/0/images/RackandPinion.jpg"]] || [[image:http://shop.showcaseantiques.com/images/items/BUYA117.jpg width="200" link="@http://shop.showcaseantiques.com/images/items/BUYA117.jpg"]] || [[image:http://www.liftturnmove.co.uk/pics/haacon_wallmounted_randp_jacks.jpg width="200" link="@http://www.liftturnmove.co.uk/pics/haacon_wallmounted_randp_jacks.jpg"]] ||
 * Rack and pinion || Bevel gears || Worm Gears ||

10.1.10 Explain a design context in which a compound rather than a simple gear train would be appropriate.
//Consider the gearing system on a metal lathe designed to be changed to cut a specific type of thread. Consider ratios, mechanical advantage and changes.//

10.1.11 Discuss the function of different types of gears in a range of objects.
//Use rack-and-pinion, bevel and worm gears.//

10.1.12 Describe a belt or chain drive system.
//Consider profile, load, changes in load, and speed.//
 * Theory of Mechanisms and Machines By C.S. Sharma, Kamlesh Purohit

10.1.13 Calculate velocity ratio for belt or chain drive systems.
For chain drives... For belt drives ...
 * Technology student on chain drives Velocity Ratio.
 * Calculate VR as you would for gears ... just ignore the chain.
 * Velocity ratio = Diameter of driven pulley/Diameter of driver //pulley//

10.1.14 Compare belt or chain drives and gear systems.
//Consider profile, load, changes in load, and speed.//
 * || Belt or chain drives || Gear systems ||
 * Profile || [[image:http://www.dkimages.com/discover/previews/941/734349.JPG width="200" link="@http://www.dkimages.com/discover/previews/941/734349.JPG"]] || [[image:http://www.mech.uwa.edu.au/DANotes/gears/intro/gearboxBIG.jpeg width="200" link="@http://www.mech.uwa.edu.au/DANotes/gears/intro/gearboxBIG.jpeg"]] ||
 * Load || The belt and chain tension strength is its limiter || Can provide or accept greater loads that belts or chains ||
 * Changes in load || Has a large range within which it can work. Change in load can occur quicker. ||  ||
 * Speed || Greater range in speeds than gears, possibly faster as well. ||  ||

10.1.18 Describe an inclined plane.
//Consider inclined planes, screw threads and wedges.//
 * [[image:http://www.generalpatton.org/education/lesson_plans/ramp.gif width="200" link="@http://www.generalpatton.org/education/lesson_plans/ramp.gif"]] || [[image:http://www.roton.com/images/16.gif width="200" link="@http://www.roton.com/images/16.gif"]] || [[image:http://www.leborgne.fr/upload/produit/21-en-zoom-plus-info.jpg width="200" link="@http://www.leborgne.fr/upload/produit/21-en-zoom-plus-info.jpg"]] ||
 * Inclined plane || screw thread || Wedge ||

10.1.19 Explain the advantage of an inclined plane.
It allows you to raise a heavy load easily, it is believed that the ancients Egyptians used this simple machine in building the pyramids. e in the content of your page here.