Kinematics
–
Kinematic Equations
http://
www.aplusphysics.com
/courses/honors/kinematics/
honors_kinematics.html
Unit #2 Kinematics
Objectives and Learning Targets
Use kinematic equations to solve problems for
objects moving at a constant acceleration in a
straight line and in free fall.
Resolve a vector into perpendicular components:
both graphically and algebraically.
Unit #2 Kinematics
Kinematic Equations
These equations can help you solve for key variables
describing the motion of an object when you have a
constant acceleration
. Once you
know
the value of
any three variables
, you can use the kinematic
equations to solve for the other two!
Unit #2 Kinematics
Key Kinematics Variables
Variable
Meaning
v
0
Initial velocity
v
Final velocity
Δx
Displacement
a
Acceleration
t
Time elapsed
Problem Solving Strategy
In using these equations to solve motion problems, it’s important to take care in
setting up your analysis before diving in to a solution. Key steps to solving kinematics
problems include:
1. Labeling
your analysis for horizontal (x

axis) or vertical (y

axis) motion.
2. Choosing
and indicating a positive direction (typically the direction of
initial
motion).
3. Creating
a motion analysis table (v
0
, v,
Δx
, a, t). Note that
Δx
is a
change
in position, or displacement, and can be re

written as x

x
0
.
4. Using
what you know about the problem to fill in your “givens” in
the table
.
5. Once
you know three items in the table, use kinematic equations to
solve
for any unknowns.
6. Verify
that your solution makes sense
.
(Note: these equations work for vertical and horizontal motion)
Unit #2 Kinematics
Sample Problem #1
–
Horizontal Motion
Unit #2 Kinematics
Sample Problem #1
–
Horizontal Motion
Unit #2 Kinematics
Sample Problem
#2
–
Vertical
Motion
Unit #2 Kinematics
Sample Problem
#2
–
Vertical
Motion
Unit #2 Kinematics
Sample Problem
#3
–
2 Stepper
Unit #2 Kinematics
Sample Problem
#3
–
2 Stepper
Unit #2 Kinematics
Sample Problem
#4
Unit #2 Kinematics
Question:
An astronaut drops a hammer from 2.0 meters above the surface of the
Moon. If the acceleration due to gravity on the Moon is 1.62 meters per second
2
,
how long will it take for the hammer to fall to the Moon’s surface?
Answer
:
Create Your Own Problem
Create your own
Horizontal
M
otion
K
inematics
P
roblem
and solve it. Feel free to make it funny, but
keep it clean.
Create a second problem making it
vertical
. Solve it
also.
Trade with a neighbor and solve
each other’s
problems before turning them in.
Unit #2 Kinematics
Comments 0
Log in to post a comment