Transcript Inclined Planes

Two-Dimensional Motion
Inclined Planes
Inclined Planes
A simple block on an incline
30°
Fg
Inclined Planes
B/c the block in on an incline,
we adjust our coordinate system to fit the incline
Y
X
30°
Fg
Aligning the X axis with the Incline
Inclined Planes
Notice the gravitational force (Fg) is
pulling straight down
Doesn’ t the Fg also pull you down
the hill?
YEP!
So, there are components of the Fg
(x and y)
Inclined Planes
There is an Fgx and an Fgy
Fgx
Fgy
Fg
Inclined Planes
Notice that the coordinate system
has been adjusted… How much?
Y
X
30°
Fg
It has been adjusted by the incline, 30°
Inclined Planes
Therefore the angle between Fg and
Fgy is…
30°
Fgx
Fgy
30°
Fg
Inclined Planes
Therefore the angle between Fg and
Fgy is…
30°
Fgx
30°Fgy
30°
Fg
Inclined Planes
Now we are able to solve for fgx and
fgy
Fgx is the force pulling the block
down the incline
Fgy is the force keeping the block in
contact with the incline
Inclined Planes
Realign the vectors (Tip-to-Tail) to
complete a right triangle and you
get…
F
30° g
30°Fgy
Fgx
Inclined Planes
Lets take a closer (magnified) look at
the similar triangle
F
30° g
30°Fgy
Fgx
Inclined Planes
Lets take a closer (magnified) look at
the similar triangle
Y
Nice!
30°
X
Fgy
Fgx
Fg
Inclined Plane Problem
A 784-N skier on a hill that makes a 35
angle with the horizontal begins to
accelerate down the hill.
–
Draw the pictorial diagram and free-body
diagram
–
What is the component of the skier’s weight
parallel to the incline plane?
–
What is the normal force?