Transcript Document

TAKS Physics
What do you know?
Main Topics
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Speed = distance / time
Acceleration = velocity change / time
Newton’s laws (F = ma)
Momentum (p = mv)
Energy (conservation)
Work and power and simple machines
Density = mass / volume
Circuits and electricity
Waves light and sound
Heat transfer
Speed = distance / time
• You might have to solve for
any of these three parts.
4A
IPC
C 1003
The diagram represents the total travel of a
teacher on a Saturday. Which part of the trip
is made at the greatest average speed?
A Q
B R
C S
D T
4A
IPC
D 1003
A car traveled 150 km in 2.5 hours. What
was its average speed in km per hour?
A
B
C
D
37.5 km/h
450 km/h
75 km/h
60 km/h
The speed of sound in human tissue is
about 1600 m/s. If an ultrasound
pulse takes 1.5 x 10-5s to travel
through a tissue, what is the thickness
of the tissue?
A 2.4 km
B 2.4 m
C 23 cm
D 24 mm
4A
IPC
D
11/05
4A
IPC
D
11/06
A cyclist moves at a constant speed of 5 m/s.
If the cyclist does not accelerate during the
next 20 seconds, he will travel ---
A
B
C
D
0m
4m
50 m
100m
4A
IPC
B
10/06
A driver traveled 270 km in 3 hours. The
driver’s destination was still 150 km away.
What was the driver’s average speed at this
point?
A
B
C
D
40 km/h
90 km/h
140 km/h
420 km/h
4B
IPC
GB
10/06
A
B
C
D
Which graph can represent an object at rest?
Acceleration =
velocity change / time
• Again, you may have to solve for any of
these quantities.
• Acceleration is measured in units of
meters per second squared
2
•m/s
4A
IPC
A
11/04
According to this graph, what was the bicycle’s
acceleration between 6 and 10 seconds?
A
B
C
D
0.0 m/s2
0.65 m/s2
1.6 m/s2
6.5 m/s2
4A
IPC
C
11/06
The table above shows experimental data collected
when four cars moved along a straight-line path.
According to these data, which car moved with a
constant acceleration of 2 m/s2?
A
B
C
D
Car Q
Car R
Car S
Car T
Newton’s laws (F = ma)
• 1st Law - objects resist acceleration
• An object at rest tends to remain at rest
and an object in motion tends to remain in
motion at the same speed and in the same
direction unless it is acted upon by an
unbalanced force.
Newton’s laws (F = ma)
• 2nd Law – F = ma
• force is equal to mass times acceleration
• weight is equal to mass times gravitational
acceleration
• gravitional acceleration (g) = 9.8 m/s2
Newton’s laws (F = ma)
• 3rd Law – for every action there is an equal
and opposite reaction
• only two forces and only two objects
• If object A applies a force on object B, then
object B MUST apply the same size force
on object A in the opposite direction.
4B
IPC
D
11/06
A hockey player pushed a puck toward the
opposite side of a level ice rink. The player
expected the puck to continue all the way
across the ice, but the puck slowed and
stopped before reaching the other side.
Which of these best explains why the puck
failed to slide all the way to the opposite side?
A
B
C
D
The puck’s temperature changed.
An upward force acted on the puck.
The puck’s momentum remained unchanged.
An opposing force acted on the puck.
4B
IPC
D
11/04
Which factor would most likely cause a
communications satellite orbiting Earth to
return to Earth from its orbit?
A An increase in the satellite’s forward
momentum
B An increase in solar energy striking the
satellite
C A decrease in the satellite’s size
D A decrease in the satellite’s velocity
4B
IPC
C
The frog leaps from its resting position at the
lake’s bank onto a lily pad. If the frog has a mass
of 0.5 kg and the acceleration of the leap is 3
m/s2, what is the force the frog exerts on the lake’s
bank when leaping?
A 0.2 N
B 0.8 N
C 1.5 N
D 6.0 N
4A
IPC
B 1003
How much force is needed to accelerate
a 1,300 kg car at a rate of 1.5 m/s2?
A 867 N
B 1,950 N
C 8,493 N
D 16,562 N
4A
IPC
D
11/05
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. What is the force of the
push by the smaller skater?
A 16 N
B 32 N
C 88 N
D 100 N
What is the net force exerted on a 90.0 kg
race-car driver while the race car is
accelerating from 0 to 44.7 m/s in 4.50 s?
A
B
C
D
9.8 N
20 N
201 N
894 N
4A
IPC
JD
11/06
4B
IPC
B
490N
11/04
How many newtons of force does a 50.0 kg
deer exert on the ground because of gravity?
A
B
C
D
49.0N
490N
59.8N
1470N
Which of these is the best description of the
action-reaction force pair when the space
shuttle lifts off from the launchpad?
4B
IPC
C
11/04
A The ground pushes the rocket up while
exhaust gases push down on the ground.
B Exhaust gases push down on air while the
air pushes up on the rocket.
C The rocket pushes exhaust gases down while
the exhaust gases push the rocket up.
D Gravity pulls the rocket exhaust down while
friction pushes up against the atmosphere.
4B
IPC
D
11/05
The picture above shows the direction in which
water leaves the scallop’s shell. Which picture
below shows the direction the scallop will move?
4B
IPC
GB
11/06
When the air is released from a balloon, the air
moves in one direction, and the balloon moves
in another direction. Which statement does
this situation best illustrate?
A What goes up must come down.
B For every action, there is an equal and
opposite reaction.
C The shape and size of an object affect air
resistance.
D The acceleration due to Earth’s gravity is
9.8 m/s2.
4B
IPC
D
1004
The illustration above shows a student about to
throw a ball while standing on a skateboard.
Which illustration below correctly shows the
skateboard’s direction of motion after the student
releases the ball?
Momentum (p = mv)
• You may be asked to solve for any of
these quantities.
• Momentum MUST be conserved. (Along
with mass and energy)
• The unit is the kilogram meter per second
•kg m/s
4A
IPC
JD
11/05
The table contains data for two wrecking balls
being used to demolish a building. What is the
difference in momentum between the two
wrecking balls?
A 300 kgm/s
B 200 kgm/s
C 150 kgm/s
D 0 kgm/s
4A
IPC
D
11/05
A 0.50 kg ball with a speed of 4.0 m/s strikes a
stationary 1.0 kg target. If momentum is
conserved, what is the total momentum of the
ball and target after the collision?
A
B
C
D
0.0 kgm/s
0.5 kgm/s
1.0 kgm/s
2.0 kgm/s
4A
IPC
HC
11/06
The 500 g cart is moving in a straight line at a
constant speed of 2 m/s. Which of the following
must to 250 g toy car have in order to maintain
the same momentum as the cart?
A An acceleration of 5 m/s2 for 2 seconds
B A potential energy of 20 J
C A constant velocity of 4 m/s
D An applied force of 5 N for 5 seconds
4A
IPC
A
10/04
Which bike rider has the greatest momentum?
A
B
C
D
A 40 kg person riding at 45 km/h
A 50 kg person riding at 35 km/h
A 60 kg person riding at 25 km/h
A 70 kg person riding at 15 km/h
4A
IPC
D
A ball moving at 30 m/s has a
momentum of 15 kg.m/s. The
mass of the ball is ___
A
B
C
D
45 kg
15 kg
2.0 kg
0.5 kg
Car velocity = 6.3 m/s
Driver velocity = 6.3 m/s
Driver mass = 100 kg
Car velocity = 0 m/s
Car velocity = 0 m/s
Driver velocity = 6.3 m/s Driver velocity = m/s
Driver mass = 100 kg
Driver mass = 100 kg
4B
IPC
630
11/06
The pictures show how an air bag functions in a
collision. How much momentum in kg m/s does
the air bag absorb from the crash-test dummy if
all the crash-test dummy’s momentum is
absorbed by the air bag?
Energy (conservation)
• Energy must be conserved
• Kinetic energy = one half mass times
velocity squared
• KE = ½ m x v2
• Gravitational potential energy = mass
times gravitational acceleration times
height
• PE = mgh
Energy (conservation)
• Energy MUST be
conserved.
• (Along with mass and
momentum.)
4A
IPC
B
11/06
A 1-kilogram ball has a kinetic energy of
50 joules. The velocity of the ball is ---
A
B
C
D
5 m/s
10 m/s
25 m/s
50 m/s
6A
IPC
C
What is the potential energy of the rock?
A. 59,000 joules
B. 64,600 joules
C. 93,100 joules
D. 121,600 joules
6A
IPC
B
11/06
What is the approximate difference in
gravitational potential energy of the two
shaded boxes?
A. 19J
B. 39J
C. 59J
D. 79J
Solar Radiation and Earth
Effect
Amount of Energy per
Second (terajoules)
Solar radiation reaching Earth
173,410
Radiation reflected back into
space
52,000
Radiation heating atmosphere,
landmasses, and oceans
81,000
Radiation producing winds and
ocean currents
370
Radiation used in
photosynthesis
40
Radiation resulting in
evaporation of water
?
6A
IPC
A
11/04
Assuming the chart contains all energy transformations in the Earth
system, how much solar radiation goes toward evaporating water?
A.
B.
C.
D.
40,000 terajoules
92,410 terajoules
121,410 terajoules
133,410 terajoules
C6H12O6 + 6O2  6CO2 + 6H2O
Glucose Water Carbon Water
Dioxide
3000 kJ 300 kJ 200 kJ 150 kJ
Why is the sum of the product’s energy in this
reaction less than the sum of the reactants’
energy?
A. Energy is given off as heat.
B. The products absorb available energy.
C. Energy is trapped in the reactants.
D. The reactants’ energy is less than the
melting point of glucose.
6A
IPC
A
11/04
Work and power and simple
machines
• Work = force times distance
• W=Fxd
• Power = work divided by time
• P=W/t
Work and power and simple
machines
• Work has NO time factor.
• If the same force is applied over the
same distance, the same work is done
even if it is done faster in one case.
• If work is done faster, more power is
used. Power is how fast work is done.
Work and power and simple
machines
• Two basic types of machines:
• Lever type simple machines
• (levers, wheel and axles, pulleys)
and
• Inclined plane type simple machines
• (inclined planes, wedges, and screws)
Work and power and simple
machines
• Simple machines may change
direction of motion. (Like a pulley)
• A machine may also trade distance
for force OR trade force for distance.
(A machine CANNOT do both.)
• A machine CANNOT increase the
WORK done.
Work and power and simple
machines
• A simple machine increases
output force over a shorter
distance by requiring the
force you put in to be applied
over a longer distance.
(You trade distance for force.)
Work and power and simple
machines
• The mechanical advantage of a
machine is force output divided by
force input.
• It is greater than 1 if the machine puts
out more force than you put in.
• It is less than 1 if the machine puts
out less force than you put in.
4A
IPC
A 1004
How much work is performed when a 50 kg
crate is pushed 15 m with a force of 20N?
A
B
C
D
300 J
750 J
1,000 J
15,000 J
4A
IPC
B
If a force of 100 newtons was exerted on
an object and no work was done, the
object must have --A
B
C
D
accelerated rapidly
remained motionless
decreased it velocity
gained momentum
4A
IPC
C
11/04
A mechanic used a hydraulic lift to raise
a 12,054 N car 1.89 m above the floor of
a garage. It took 4.75 s to raise the car.
What was the power output of the lift?
A
B
C
D
489 W
1815 W
4796 W
30,294 W
4A
IPC
C
11/05
A horizontal force of 600 N is used to push a
box 8 m across a room. Which of these
variables must be known to determine the
power used in moving the box?
A The weight of the box
B The potential energy of the box
C The time it takes to move the box
D The length of the box
A woman lifts a 57-newton weight a distance
of 40 centimeters each time she does a
particular exercise. It takes her 0.60 second
to lift the weight. How much power does she
supply for lifting the weight one time?
A
B
C
D
24 W
34 W
38 W
95 W
4A
IPC
c
11/06
An advertisement claims that a certain truck
has the most powerful engine in its class. If
the engine has more power, which of the
following can the truck’s engine do,
compared to every other engine in its class?
A
B
C
D
Produce fewer emissions
Operate more efficiently
Perform work faster
accelerate longer
4A
IPC
HC
11/06
A person pushes a large box across a level
floor by applying a horizontal force of 200 N.
If the person pushes the box a distance of
5 meters in 10 seconds, how much work
does the person do on the box?
A
B
C
D
2000 joules
1000 joules
400 joules
100 joules
4A
IPC
B
10/06
4A
IPC
HC
11/04
The weight lifter used a force of 980 N to raise
the barbell over her head in 5.21 seconds.
Approximately how much work did she do in
raising the barbell?
A 380 L
B 982 J
C 2,000 J
D 10,000 J
4D
IPC
FA
11/04
A
C
B
D
Which lever arrangement requires the least
effort to raise a 500 N resistance?
4D
IPC
HC
11/06
Which configuration of pulleys and belts shown
below will result in the fastest rotation of spindle
2?
A
C
B
D
4D
IPC
C
11/06
Which of these represents a properly
balanced system?
4D
IPC
GB
The diagram shows an electric motor lifting a 6 N
block a distance of 3 m. The total amount of
electrical energy used by the motor is 30 J. How
much energy does the motor convert to heat?
A
B
C
D
9J
12 J
18 J
21 J
Efficiency
• Efficiency is calculated by dividing
work output by work input and
multiplying it by 100%.
• The efficiency can NEVER be
more than 100%.
4D
IPC
GB
11/04
What is the efficiency of an air conditioner
if there is a work input of 320 J and a work
output of 80 J?
A
B
C
D
4%
25%
240%
400%
Density = mass / volume
• Be able to solve for any of the three
values.
• The unit is grams per milliliter or
• grams per cubic centimeter
• g/ml or g/cm3
Circuits and electricity
• Voltage = current x resistance
• V = IR
• Power = current x voltage
• P = IV
6F
IPC
A 1004
How much current is flowing through this circuit?
A 0.32 A
B 3.1 A
C 4.0 A
D 12.5 A
6F
IPC
A
10/0
6
In this circuit, how much current flows through
the lightbulb?
A. 0.75 amp
B. 1.50 amps
C. 2.0 amps
D. 3.0 amps
6F
IPC
C
10/0
6
The bulb will light when a current supplied by at
least one 1.5 V battery is available. Which
current will fail to light the bulb?
6F
IPC
A 1003
Which switch, if opened, will cause the lightbulb to
stop glowing?
A. Q
B. R
C. S
D. T
6F
IPC
G
1003
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
6F IPC
JD
10-04
A
C
Which circuit is built so that if one lightbulb goes
out, the other three lightbulbs will continue to glow?
B
D
Waves
light and sound
• Velocity = frequency x wavelength
• v=fxl
• Two types of waves:
compression and transverse waves
• Sound is a compression (longitudinal)
wave
• Light is a transverse wave.
Properties of Waves
• Interference - waves
cross over each other
• can increase or decrease
amplitude
Properties of Waves
• Resonance - the vibration
of one object causes the
vibration of another object
without contact
Properties of Waves
• Reflection - a wave ounces off
a boundary
• The angle of reflection is equal
to the angle at which the wave
meets the boundary.
Properties of Waves
• Refraction - the bending
of a wave as it changes
speed moving from one
medium to another
Properties of Waves
•Diffraction - the
bending of a wave
as it moves around
an obstruction or
through an opening
Properties of Waves
• Polarization - allowing
only one orientation of a
transverse wave to pass
• Only transverse waves can
be polarized.
5A
IPC
B 1004
Which illustration best demonstrates
compression waves?
5B
IPC
C
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
because of --A. interference
B. the Doppler effect
C. resonance
D. standing waves
5A
IPC
A
10/06
Which label on the model represents a
wavelength?
A. Q
B. R
C. S
D. T
An empty cup was tightly covered with plastic
wrap, and a few grains of salt were sprinkled
on top of the plastic. When a tuning fork was
struck and placed slightly above the plastic
wrap, the salt began to move. Which
characteristic of waves does the movement
of the salt best demonstrate?
A.
B.
C.
D.
Echo formation
Diffraction
Resonance
Specular reflection
5B
IPC
C
11/06
Laser Light Striking a DVD
5B
IPC
D
11/06
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. Conduction
B. Refraction
C. Magnification
D. Reflection
5B
IPC
A
11/04
The pitch of a sound made by plucking a
guitar string is determined by the ---
A. frequency of the vibration produced
B. strength of the plucking force
C. distance between the strings
D. shape of the guitar body
A tuning fork with a frequency of 256 Hz
vibrates when struck. Because of these
vibrations, a nearby tuning fork begins to
vibrate without being struck. Which of the
following best accounts for the vibrations
of the second tuning fork?
A. Resonance
B. Polarization
C. Diffraction
D. Refraction
5B
IPC
A
11/05
5B
IPC
B
11/06
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. Polarization
B. Resonance
C. Reflection
D. Diffraction
5B
IPC
B
11/04
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 the air.
The bending of light as it passes from one
medium into another is known as --A. Reflection
B. Refraction
C. Diffraction
D. Polarization
5B
IPC
F
11/05
A surface wave generated by an earthquake was
recorded at Seismic Station 1. Forty seconds later
the same wave was recorded at Seismic Station 2.
What accounts for the time difference?
A.The origin of the wave is closer to Seismic Station 1.
B.The speed of the wave decreases with distance.
C.The wavelength is longer at Seismic Station 2.
D.The wave frequency increases when the wave
passes through soil.
5B
IPC
B
11/04
Which wave has the greatest velocity?
5B
IPC
D
11/04
Which wave has the least velocity?
5B
IPC
D
11/06
Diverging lenses are useful to people who
suffer from nearsightedness because the
lenses can cause images of distant objects to
be focused on the retina. Lenses allow images
to be focused on the retina because of --A. Diffusion
B. Reflection
C. Diffraction
D. Refraction
5B
IPC
B
11/05
The diagram shows waves approaching a barrier. Which pattern will be
formed after the waves pass through the opening in the barrier?
Heat Transfer
• Conduction - transfer from one particle to
another with contact
• Convection - transfer of heat containing
particles in a fluid due to differences in
density
• Radiation - transfer from one particle to
another without the need for contact
6B
IPC
B
Heat convection occurs in gases and liquids.
Heat convection does not occur in solids
because solids are unable to --A. absorb heat by vibrating
B. transfer heat by fluid motion
C. emit radiation by reflecting light
D. exchange heat by direct contact
6B
IPC
B
11/06
The transfer of heat by the movement of air
currents in Earth’s atmosphere is an
example of --A. Conduction
B. Convection
C. Radiation
D. Fusion
6B
IPC
A
10/04
A man who was sleeping wakes up because
he hears the smoke alarm go off in his house.
Before opening the bedroom door, the man
feels the door to see whether it is warm. He
is assuming that heat would be transferred
through the door by --A. Conduction
B. Convection
C. Radiation
D. Compression
6B
IPC
C
10/06
In winter the air just above the top bunk of a bunk bed is
warmer than the air just above the bottom bunk because warm
air rises. Which of the following describes the method of
heating that causes this difference in temperature?
A. Radiation from the room
B. Heat transfer through walls
C. Convection currents in the room
D. Heat conduction through the bed
6B
IPC
A
10/06
Which of these is the best example of heat
transfer by radiation?
A.
B.
C.
D.
A satellite is warmed by sunlight.
Butter melts on warm bread.
A ceiling fan cools a warm room.
Puddles of water cool a warm tile floor.
6B
IPC
D
10/04
Temperatures of Water in
Different Containers
Container
Initial
Temperature
(oC)
Final
Temperature
(oC)
P
90
83
Q
90
76
Container P and Container Q each were filled with
0.5 liter of water. The water was heated to 90oC.
The table shows the temperatures after both
containers were allowed to cool for 3 minutes.
Compared to Container Q, Container P is a better --A. conductor
B. absorber
C. radiator
D. insulator
6B
IPC
D
11/04
A
C
B
D
In which container is the substance unable to
transfer heat by convection?
6B
IPC
J 1003
The primary way liquids and gases transmit
heat is by the process of --A. reflection
B. convection
C. radiation
D. convection
6B
IPC
C
A solar heater uses energy from the sun to
heat water. The heater’s panel is painted
black to --A. Improve emission of infrared radiation
B. Reduce the heat loss by convection currents
C. Improve absorption of infrared radiation
D. Reduce the heater’s conducting properties