
An inclined plane provides less effort.

The trade off is greater distance to travel.

Used to reduce the force needed to overcome the
force of gravity when lifting or lowering a heavy
object.
Applied distance (d)
Height (h) of
Resistance load
Mechanical Advantage:
I.M.A: = d / h
A.M.A: = FW / FA
A person is pushing a block up a ramp that is 5 meters high and 10 meters
long. The ramp has 20° angle. The block has a mass of 30 N and it is taking
them 20 N of force to push it.
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
k.
Draw a free body diagram of the above.
What is the Applied Force (FA)? 20N (Given)
What is the Resistance Force (FW)? 30N (Given)
What is the Effort Distance (d)? 10m (Given)
What is the Resistance Distance (h)? 5m (Given)
What is the I.M.A. of this system? IMA =2
What is the A.M.A. of this system? AMA =1.5
What is the Work OUT (Wout)? 150 J
What is the Work IN (Win)? 200 J
What is the work lost to friction? (WF) 50 J
What is the Efficiency of this machine? Eff = 75%
Example #2
A civil engineer must design a wheelchair accessible ramp next to a
set of steps leading up to a building. The height from the ground to
the top of the stairs is 4 ft and the base of the incline is 48 ft long.
a. Sketch the inclined plane described above
b. Using the known height and base length, what is the distance of
the slope of the ramp
c. What is the ideal mechanical advantage of the ramp
d. If a person and wheelchair have a combined weight of 205 lb,
how much ideal applied force is required to travel up the ramp

A modification of an inclined plane that moves.

It is made of two inclined planes put together.

Instead of the load being moved up an inclined plane, the inclined
plane moves the load.
The wedge embodies the same principles as the incline in
the sense that a smaller force working over a longer
distance can produce a larger force acting through a small
distance.
As a double incline, its ideal mechanical advantage is the
ratio of the depth of penetration L to the amount of
separation achieved h.
Mechanical Advantage:
I.M.A: = d / h
A.M.A: = FOUT / FA
h
d
Example #1
Using the wedge diagram
below, calculate the:
a. I.M.A
b. A.M.A
c. Efficiency
250 lbs
3 in
700 lbs
10 in

A screw is an inclined plane wrapped around a central
cylinder.

The inclined plane allows the screw to move itself when
rotated.
ADVANTAGES:
DISADVANTAGES:
FIN < FOUT
DIN > DOUT
Less Applied Force Needed
More Distance Needed
 When using a 1st or 2nd class lever, pulleys, inclined planes,
screws, wheel and axle (wheel driving the axle) or wedges they
require less applied force to move the resistance force.
 Requires more distance of the applied force than the resistance
force which results in moving at a slower speed.
 These machines have a mechanical advantage greater than 1.
 Examples: pliers, screwdriver, loading ramp, screws, splitting
wedge.
ADVANTAGES:
DISADVANTAGES:
DIN < DOUT
FIN > FOUT
Less Distance Needed
More Applied Force Needed
 When using a 3rdclass lever or wheel and axle (axle driving the
wheel) they require less distance of the applied force to move the
resistance force.
 Requires more force of the applied force than the resistance force,
which results in moving at a faster speed.
 These machines have a mechanical advantage less than 1.
 Examples: Bicycle, broom, fishing pole, car wheel & axle, shovel,
ball bat, or tennis racket.