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

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

3. Inclined Plane
The effort force increases as the slope steepens.

4. 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…]

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

6. Wedge
MAwedge = slope length
wedge width
width
slope length

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

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

9. 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]

10. 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

11. 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

12. 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!!!