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TAKS Physics Review
DAY 1
Objective 5 - Physics
 Force
and motion
 Newton’s laws
 Waves
 Conservation of energy
 Heat transfer
 Electrical circuits
 Simple Machines
Motion: Speed

Speed (S) - a distance traveled in a given
amount of time.
LOOK at the formula on your chart:
Speed = Distance Traveled
Time
In other Words: Speed is just the distance
traveled over time.
Speed Example: I.4A 10th Spring
2003
First let’s list what we know and what
we want to find out.
We know: Distance traveled= 150 km
Time =2.5 Hours
We want to find out: ??Average speed???
So what is the difference between
speed and velocity?
Velocity is the vector quantity of speed.
Remember: a vector needs to have a
magnitude and direction.

Therefore: Velocity is just the speed
(magnitude) in a given direction.
Let’s come up with some examples!!!
Motion: Acceleration
When an object's velocity changes, it
accelerates. Acceleration shows the change
in velocity in a unit time.
Let’s look at the formula:

Acceleration = final velocity – initial velocity
change in time
In words: Acceleration is just the change of
velocity over a period of time.
Example
A roller coaster has a velocity of 3 m/s and
an acceleration of 15 m/s2. How many
seconds will it take the roller coaster to
reach its maximum velocity of 27 m/s?
First let’s list what we know and what we
want to find out.
We know:
The current (or initial) velocity: 3 m/s, vi
The acceleration: 15 m/s2, a
The maximum (or final) velocity: 27 m/s, vf
We want to find out how much time it will
take the roller coaster to accelerate from 3
m/s to 27 m/s.
final velocity  initial velocity
acceleration 
change in time
We need to solve for time so we need to rearrange
our formula and solve for change in time.
First:
acceleration x change in time = final velocity – initial velocity
Then solve for time:
change in time = final velocity – initial velocity
acceleration
SOLVE IT!!!
Motion: Momentum
Objects in motion are said to have a momentum. This
momentum is a vector. It has a size and a direction.
momentum is equal to the mass of the object
multiplied by the object's velocity. The direction of the
momentum is the same as the direction of the object's
velocity.
From our formula chart:
Momentum = mass x velocity
Momentum
Momentum is a conserved quantity in physics.
 One object might change momentum, say losing
some momentum, as another object changes
momentum in an opposite manner, picking up
the momentum that was lost by the first.

ρ1= ρ2
therefore
m1v1 = m2v2
Example
7. The 500 g cart is
moving in a straight line
at a constant speed of
2 m/s. Which of the
following must the 250 g
toy car have in order to
maintain the same momentum as the cart?
F An acceleration of 5 m/s2 for 2 seconds
G A potential energy of 20 J
H A constant velocity of 4 m/s
J An applied force of 5 N for 5 seconds
Newton’s Laws
Newton's First Law of motion
(Law of Inertia)

An object at rest tends to stay at rest and an object in
motion tends to stay in motion with the same speed and
in the same direction unless acted upon by an
unbalanced force.
Newton’s Laws cont.
Newton's second Law of motion
(Law of acceleration)
 The second law states that the
acceleration of an object is dependent
upon two variables –
the net force acting upon
the object and the mass
of the object.
Newton’s Laws cont.
Newton's third Law of motion
(Law of action and reaction)

For every action, there is an equal and opposite
reaction
Back to our Formula Chart

Force - a push or a pull on an object that
will result in the acceleration of the object.
F = ma

Force is measured in
NEWTONS (N)

A newton is simply a
kg*m
s2
Formula Chart contd.
Work - occurs when a force causes an object to
move in the direction of the force
W=Fd
Work is measured in
JOULES (J)
A joule is simply a newton*meter
Formula Chart cont.
Power - The amount of work that gets done
over a certain amount of time.
P= W_
t
Power is measured in
WATTS (W)

A watt is simply a joule
s
Formula Chart cont.
%efficiency is simply the relation of how
much work are you getting out related to
how much work you actually put into a
process.
From our chart:
%efficiency = work output X 100
work input
Sample Problems
1.
You must exert a force of 4.5 N on a
book to slide it across a table. If you
do 2.7 J of work in the process, how
far have you moved the book?
a. .30 m
b. .79 m
c. .60 m
d. 1 m
Sample Problems cont.
Sample Problems cont.
Sample Problems cont.
Sample Problems cont.
Sample Problems cont.
Sample Problems cont.
Energy
Is defined as the
Ability to do Work
There are two
Types: Kinetic (Energy of Motion)
and
Potential (Stored Energy)
Kinetic Energy
KE = ½ m v
2
Ex: A moving car
has the ability to
do work on the light
pole if it hits it.
Potential Energy
2 possibilities
Gravitational PE
-Object lifted to
some height
Elastic PE - A
stretched or
compressed object
(spring or rubber
band)
Gravitational Potential Energy or
Will it fall?
GPE = m g h
m is the mass of the
object in Kg,
g is the acceleration
due to gravity which is
9.8 m/s2 on earth and
h is the height in meters
Use the formula page!
PE = mgh
41 What is the
potential energy
of the rock?
mA=59,900
95 kg joules
g = 9.8
2 h =joules
B
64,600
m/s
100 m
joules
2 x 100
95Ckg93,100
x 9.8 m/s
D 121,600
= joules
93,100 joules C
Law of Conservation of
Energy
 Energy
can change forms,
but is never created nor
destroyed
 Loss in one form = gain in
an another form
 A falling object speeds up
as it falls to the ground; PE
decreases as KE increases.
The KE it has at impact =
the PE it had before it fell.
Example: A falling object speeds
up as it falls to the ground;
PE decreases as KE
increases, the KE it
has at impact with
the ground is equal
to the PE it had
before it fell
Sample Problems
Sample Problems cont.
Sample Problems cont.
36
PHYSICS REVIEW DAY 2
Waves - Energy carried by
rhythmic disturbances
Two types:
 1. E.M. radiation
move through
empty space
 2. Mechanical
require a medium
(air, water or any
type of matter) for
movement

Waves - 2 Types
All waves have similar properties
 Frequency-
the number of vibrations
per second or the speed of the
movement of the vibrating particles
 Amplitude – the size of the movement
of the vibrating particles
 Both are controlled by the disturbance
that created the waves
Velocity of all waves - v=f
λ
f-frequency and λ is
wavelength (distance
between identical points on
two consecutive waves)
Reflection- bounce off
barriers in regular ways
Refraction- waves can
change direction when
speed changes
The speed of a wave is the distance the wave
travels in one unit of time. The speed of a
wave is measured in units per second (m/s). A
waves velocity is its speed in a particular
direction.
Frequency is a measure of how many
wavelengths pass a particular point in one unit
of time. Measured in hertz (hz). One hertz is
equal to one wave per second.
-So, if four complete wavelengths pass you
every second, the frequency is four waves per
second, or four hertz.
And the answer is? J
3300 Hz
38 At 0°C sound travels through air at a speed
of 330 m/s. If a sound wave is produced
with a wavelength of 0.10 m, what is the
wave’s frequency?
F 0.0033 Hz
Use the formula chart!!!
G 33 Hz
Velocity
=
f
λ
OR
H 330 Hz
J 3300 Hz
330 m/s = f x 0.10 m
Transverse Waves
 In
Transverse Waves
particles vibrate at right
angles to the direction
the wave travels.
 Ex. E. M. Waves,
waves on a slinky or
rope coil, ocean waves
Longitudinal or
Compress ional Waves
Vibrating particles move
back and forth along
the direction of the
wave velocity
Parts consist of
compressions and
rarefactions
Ex. Sound Waves
Sample Problem
Sound Waves move through
matter not through empty
space.
32 One tuning fork is struck and
placed next to an identical fork. The
two forks do not touch. The
second tuning fork starts to vibrate
Resonance is the vibration
because of —
of another object struck by a
wave of the correct
F interference
frequency. Since the forks
G the Doppler effect are identical, the second
one receives the correct
H resonance
frequency to begin vibrating.
J standing waves
Heat Transfer
 Difference
between Heat and
Temperatute.
Heat is energy that is transported from
warmer objects to colder objects.
Temperature is a measure of the amount
of kinetic energy and momentum atoms
and molecules have in an amount of gas,
liquid, or solid.
transfer of heat through a SOLID,
where kinetic energy is transferred from
molecule to molecule
 Objects MUST touch

– THINK of a CONDUCTOR

Convection:
transfer of heat that
occurs from the motion
of fluid in LIQUID or
GAS that is caused by
differences in
temperature
transfer of heat by electromagnetic WAVES
that are produced by thermal motion of
molecules and atoms
 SUN!!!
 NO TOUCHING

Sample Problems
Sample Problems cont.
Sample Problems cont.
Electrical Energy -
Moving electrons in a path is
electricity
Electrical Potential Difference (v) is measured
in Volts
 The rate of moving electric charges, Electric
Current (I), is measured in Amperes
 Resistance or opposition to the movement of
the energy is called Resistance (R).

Circuits – 2 types
 Series
circuits are
the most simple.
 One (1) path for the
current to travel.
 Contains an energy
source, a path, and a
load (something for
it to do, like a lamp)
Circuits – 2 types
 Parallel
circuits
provide more
than one path
for the current
to travel.
 Most circuits are
parallel, since if
one lamp goes
out, the others
can stay lit.
6. Which switches, if opened, will
cause the light bulb to stop
glowing?
F. Q
G.
R
It is the only
H. S
switch in
J. T
series to
both the
battery and
light.
USE THE FORMULA SHEET!!

What is the current in a copper wire that
has a resistance of 2 ohms and is
connected to a 9 volt electrical source?
A.
B.
C.
D.
0.22 amp
4.5 amps
11.0 amps
18.0 amps
V = I R so,
9V = I x 2 ohms
or 4.5 amps
Remember
Use
your Equation Sheet
Use
your Calculator
Use
your Periodic Table