|
Work, Energy, and the Simple Machine: Lever, Wheel and
Axle, Pulley . United Learning. 2001. unitedstreaming. 1 August 2007
<http://www.unitedstreaming.com/>
graphic from http://www.teacherfiles.com/animated/animated_science.htm
lever information taken
from http://www.enchantedlearning.com/physics/machines/Levers.shtml
pulley pictures
http://www.dorlingkindersley-uk.co.uk/static/cs/uk/11/clipart/sci_forces/book_sci_forces.html
http://en.wikipedia.org/wiki/Pulley
|