Transcript TOTT obj. 5 - Mr. Wells` wikispace

Taking on the TAKS
(TOTT)
February 2008
Objective 5- Physics
Objective 5: Physics
Motion, Forces, and Energy
*8 questions on the 10th grade TAKS
*11 questions on 11th grade TAKS
FORMULA CHART
Another tool for
success on the test.
Formula in Words
Formula in Symbols
Clarification…….
1
Clarification…….
Sometimes the
question will use the
word VELOCITY
instead of speed.
v=d
t
• A place to
look for a
missing
number
• Determine
what the
units
should be
Practice Problem #1
A person pushes a large box across a level floor
by applying a horizontal force of 200 N
N. If the
person pushes the box a distance of 5 meters in
10 seconds,
seconds how much work does the person do
on the box?
A 2000 joules
B 1000 joules
C 400 joules
D 100 joules
Work =force x distance
W=Fd
W= (200N)(5m) = 1000 joules
*notice 10 seconds was not needed
Practice Problem #2
In this circuit, how much
current flows through
the light bulb?
A
B
C
D
0.75 amp
1.50 amps
2.0 amps
3.0 amps
Current = voltage = V
resistance
R
Current = 1.5 volts = 0.75 amp
2.0 ohms
Let’s Practice……..
*work on problems #1-5 on your
worksheet
Two steppers…..
•Problems that involve the use of
two formulas
•The two formulas have a common
term
Two Stepper #1
What is the net force acting on a 90.0 kg racecar driver while the race car is accelerating
from 0 to 44.7 m/s in 4.50 s?
A 9.8 N
a=vf-vi
F=ma
B 20 N
Dt
m= 90.0 kg
C 201 N
a=9.9
____
m/s2
a=44.7m/s-0m/s
D 894 N
4.50 s
F= ?
We need to know “a”, to get our answer.
Let’s find another equation.
Two stepper #2………………
F=ma
m=40 kg
2.5 m/s2
a=_____
..another
equation
Starting from rest at the center of a
skating rink, two skaters push off from
each other over a time period of 1.2 s.
s
What is the force of push by the smaller
skater?
A 16 N
B 32 N
C 88 N
D 100 N
a=vf-vi
Dt
a= 3.0 m/s-0m/s
1.2 s
Two steppers: other common
combinations
F=mxa
and
W=Fxd
W= F x d
and
P=W
t
Conceptual Questions
The Sun is
the #1 source
of energy for
Earth
Energy: the ability to cause
change
Energy can be transformed from one
form to another.
UV
Energy can be transformed from one
form to another.
Photosynthesis
Which of the following is an example of solar energy
being converted into chemical energy?
a. Plants producing sugar during the day
b. Water evaporating and condensing in the
water cycle
c. The sun unevenly heating Earths surface
d. Lava erupting from volcanoes for many days
The Law of Conservation of Energy:
The total energy of a closed system
is constant.
An inventor claims to have created an internal
combustion engine that converts 100 kJ of
chemical energy from diesel fuel to 140 kJ of
mechanical energy. This claim violates the
law of conservation of -a. momentum
b. inertia
c. energy
d. mass
A helpful hint……………..
Gravitational potential energy = Potential Energy
If the energy of a closed system changes,
then you will observe changes in the
system
Working
Heating
W=F x d
Q=mcDt
•Feel a
temperature
change
Energy of
a System
•See a change
in motion
Radiating
V = lf
•Hear sound
•See light
Heating……
• Convection!!!!!!
• The answer any time
the words: air,
liquid, water or fluid
are used.
• When in doubt
guess convection.
Wave behavior……….
•Reflection: echo
When a DVD is read, laser light touches the
DVD surface and is then measured at location
A. What allows light to return to location A after
striking the DVD surface?
a.
b.
Conduction
Refraction
c. Magnification
d. Reflection
Wave behavior……………..
•Refraction: bending of wave
when it enters a new substance
(medium)
air
water
When trying to spear a fish in water, a
person needs to take into account the way
light bends as it moves from water into air.
The bending of light as it passes from one
medium into another is known as -a.
b.
reflection
refraction
c.
d.
diffraction
polarization
Sound….requires vibrations
•Resonance: one vibrating object
causing another object to start
vibrating (musical instruments)
A guitar player is seated next to a piano. The
piano player strikes an E key on the piano.
The guitarist reports that this causes the E
string on his guitar to vibrate. What is the
name of this phenomenon?
a.
b.
Polarization
Resonance
c.
d.
Reflection
Diffraction
Wave behavior……………….
•Diffraction: waves spreading out
when they pass through an
opening
D
The diagram below shows
waves approaching a
barrier. Which pattern will
form after the waves pass
through the opening in the
barrier?
A
B
C
D
Don’t forget……….
• Speed of light and sound
TOTT:
You can do it!
Two Steppers
Convection