# Simple Machines: Inclined Plane, Wedge, Screw

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Simple Machines: Inclined Plane, Wedge, Screw
Unit 6 – Lecture 2

Inclined Plane Composed of an even, sloping surface
makes it easier to move a load to a higher elevation MA = slope length height of inclined plane slope length height

Inclined Plane The effort force increases as the slope steepens.

Practice What is the MA of the inclined plane shown below?
When a hill is very steep, what do we do to decrease the effort force we have to apply to move an object? [think about driving…]

Wedge A wedge is a modified inclined plane.
used for separating or holding composed of: one inclined plane two inclined planes joined together

Wedge MAwedge = slope length wedge width width slope length

Screw A screw is also a modified inclined plane
MAscrew = circumference of screw threads per cm

Practice Inclined Planes Length = Height = 3 m 3768 m MA = 1256
Length = 581 m MA = 3768 m 145.3

Practice Calculate the Efficiency
A box weighing 100 N is pushed up an inclined plane that is 5 meters long. It takes a force of 75 N to push it to the top, which has a height of 3 meters. HINT: Find & compare the MAs [IMA and AMA]

Practice IMA = what the machine SHOULD do
Calculate the Efficiency A box weighing 100 N is pushed up an inclined plane that is 5 meters long. It takes a force of 75 N to push it to the top, which has a height of 3 meters. HINT: Find & compare the MAs [IMA and AMA] IMA = what the machine SHOULD do length / height = 5 / 3 = 1.67 AMA = what the machine actually does Force(resistance) / Force(effort) = 100 / 75 = 1.33

Practice Is the actual efficiency less or more?
Calculate the Efficiency A box weighing 100 N is pushed up an inclined plane that is 5 meters long. It takes a force of 75 N to push it to the top, which has a height of 3 meters. HINT: Find & compare the MAs [IMA and AMA] Is the actual efficiency less or more? So…what is the process you do to find out how much of the ideal the actual really is? (1.33 / 1.67) * 100 = 79.64

Homework Complete NOTES: Inclined Planes w/s [page 7]
Mechanical Advantage w/s [pg 8] NOTES: you will be completing through page 11 by tomorrow, so if you finish early, you may want to continue working your projects are due MONDAY!!!