# Kinematic Equations - Plain Local Schools

Mechanics

Nov 14, 2013 (4 years and 6 months ago)

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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

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
-
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
.

(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?

:

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