Over the course of the unit, I have collected meta notes on
each worksheet or activity that we did.
·
I learned that when you solve for the time, plug
in Vix for initial velocity.
·
Always plug the acceleration or displacement in
as a negative number.
·
When a problem does not give you the Vi in the
horizontal or vertical direction, split the velocity into components and use
cosign to solve for the Viy and Vix.
·
Remember:
o
How long/ how far: displacement (change in X)
o
How fst: velocity
·
The only formula that can be used in the
horizontal direction is:
Vx= Change in
Xx
T
Rules:
1.
If an object starts at rest or is dropped then
the Vi is 0.
2.
When something is falling down in the vertical
direction, the acceleration and displacement is negative.
3.
The only force acting on an object falling is
gravity, therefore the acceleration is negative because gravity is going
downward.
4.
Whenever an object is at it’s highest point,
before it turns around and accelerates downward, the velocity is 0 at the
highest point.
5.
The only formula that can be used in the
horizontal is Vxx equals change in Xx over change in time.
6.
When an object is thrown up and the returns to
the ground vertically, the displacement is always 0.
7.
If the path of an object in moving upward, the
displacement is positive
8.
If the path of an object is moving downwards,
the displacement is negative
9.
Always use cosign to solve for the components of
Vix and Viy
10. When using the quadratic formula, always use the positive answer for time.
Formulas:
o
x= 1/2at^2+viy(t)
o
vf=at+ vi
o
vf^2=vi^2+2(acceleration)(change
in x)
o
a= change in v/ change in t
Key:
Here
are the models the apply to the vertical or horizontal sides. When doing a goalless
problem, here are all the variable to solve for:
Vertical:
o
-Unbalanced forces
o
CAPM
o
UFPM
o
Acceleration
o
vf=at+ vi
o
x= 1/2at^2+viy(t)
o
vf^2=vi^2+2(acceleration)(change
in x)
Horizontal:
o
BFPM
o
CVPM
o
Constant velocity
o
Vx= Change in Xx
T
Example:
NASA launches a
rocket horizontally with a 7.0 m/s off a crater on the moon. How far will it
travel horizontally before it strikes the ground outside the crater 15m below?
(Disregard the lack of gravity outside of earth).
First, write all the horizontal and vertical knowns and
unknown. As we solve for each variable we will go back and plug in what we
found.
Horizontal:
o
Vi= 7m/s
o
Displacement= ?
o
t= ?
o
a= -10m/s
Vertical:
o
displacement= 15m
o
a= -10m/s
o
Vi= 0
o
T=?
First, use the following formula to solve for the time.
Change in X= 1/2at^2+Vit
-15= ½(-10)t^2+0t
-15=-5t^2
- 3 -3
t= 1.73s
Now plug in the time into the horizontal equation to find
the displacement.
Velocity= change in X
Time
7= X
1.73
displacement= 12.11m
Now plug in the variable solved for into the horizontal and
vertical lists.
Horizontal:
o
Vi= 7m/s
o
Displacement= 12.11m
o
t= 1.73s
o
a= -10m/s
Vertical:
o
displacement= 15m
o
a= -10m/s
o
Vi= 0
o
T= 1.73s
Describe the motion
of the rocket in the x-direction and explain why it moves in that manner.
The rocket moves in the x directions with no acceleration and
the only force acting on it is gravity. Gravity only affects the vertical
direction.
Describe the motion
of the rocket in the y-direction and explain why it moves in that manner.
It drops 15m and moves downwards with acceleration of 10m/s,
with only the force of gravity acting on it. There is an unbalanced force of
gravity, which causes it to speed up.
The picture above is a projectile motion map, showing the projectile motion of a ball being thrown. The ball is thrown upward in its path, reaches the top, and then changes direction and accelerates downward.
Projectile Motion in Real Life:
Projectile motion can be applied in engineering designs. In oorder to design machinery, you have to have a concept of gravitational acceleration and the ability to predict the path of motion usuing mathematical formulas. By being able predict the trajectory of objects, can help students complete labs more efficiently. At the conclusions of this unit, students had many assets under their toolbelts to solve labs. We could use Pasco capstone, different kinematics formulas to solve for a specific variable, or use a force diagram and scale to solve for different forces.
