make work easier to do by: increasing the size of an applied force changing the direction of an...
TRANSCRIPT
Make work easier to do by:
• Increasing the size of an applied force• Changing the direction of an applied force• Changing the distance over which a force acts
There will always be a trade-off!!!
Create three machines to lift the mass in three different ways
Use the following materials:•Ruler•Marker•tape
http://www.pencils.com/sites/default/files/imagecache/product/Color_Rulers.jpg
http://finepointdesign.com/wp-content/uploads/2011/01/DSC05618_markers_web.jpg
http://27.media.tumblr.com/tumblr_lhs14t9rhm1qzur0wo1_400.jpg
http://physics.fau.edu/observatory/Images/100gmass.jpg
Sketch, label, and describe eachdifferent method.
http://cnx.org/content/m23853/latest/ http://www.the-office.com/summerlift/pulleybasics.htm
http://www.g9toengineering.com/resources/simplemachines.htm
http://en.wikipedia.org/wiki/Ferris_wheel http://makeitgo.wikispaces.com/wedges
http://www.schnauzerlover.com/ramp.htm
What goes in…
Input is also called “effort:”-Effort force is the force applied to a machine-Effort distance is the distance across which the effort is applied
What comes out…
http://tech.texasdi.org/simplemachines http://elimeirkaplan.com/blog/?p=608
Output is also called “resistance:”-Resistance force is the force exerted by a machine-Resistance distance is the distance across which the machine applies effort
FULCRUM
LOAD
EFFORT
Fixed point about whichthe lever rotates
The mass beinglifted by a lever
Force used tolift the load
Review: Force is a push or a pull on an object, and is measured in Newtons
is between the effort and the loadFULCRUM…
RESISTANCE DISTANCE…EFFORT DISTANCE…
Explore the relationship between effort force required to lift a load, and the length of the resistance distance.
Resistance Force = ____ N
Use the following materials:•Ruler•Marker•Tape•Spring Scale•100-g mass
Data Collection: - repeat for 3 trials at this fulcrum position for consistency - average the effort needed for this fulcrum position
Trial Fulcrum Position (cm) Resistance Distance(cm) Effort Force (N)
1
2
3
Average
Data Table 1: Effort force measurements for fulcrum positioned at ____ cm
Number of times the input is increased by a machine
distance resistance
distanceeffort
R
E
d
dIMA
forceEffort
force Resistance
E
R
F
FAMA
The mechanical advantage in a “perfect” world; predicted mechanical advantage
The real mechanical advantage that results when the machine is in use
What did you determine, through your experiment, about the relationship
between the (length of the) resistance arm and the effort needed to lift the load?