Download (f) and the mirror.

SPRING PHYSICS 2016
Journals
Journal #1
1/7/2016
1. During the spin cycle of a washing machine, the clothes
stick to the outer wall of the barrel as it spins. If the radius
of the barrel is 0.260 m and the time for one revolution is
0.0330 s, how fast is the barrel spinning?
49.5 m/s
2. A battery-powered plane is suspended from a string and
flying in a horizontal circle. The plane makes a complete
circle every 2.15 seconds. The radius of the circle is 0.950 m.
If the plane has a mass of 0.631 kg determine the
centripetal force acting on the plane.
5.12 N
DO NOT ROUND UNTIL THE END.
Journal #2
1/11/2016
1. A 45 kg merry-go-round worker stands 6.3 m from
the center of the ride and it takes 9.65 s for the ride
to make one revolution.
A. What is the centripetal force acting on the worker?
120 N
B. What type of force provides the centripetal force?
friction
Journal #3
1.
1/13/2016
Determine the force of gravitational attraction between the
earth (m = 5.98 x 10 24 kg) and a 70.0 kg physics student if the
student is in an airplane at 40000 feet above earth's surface. This
would place the student a distance of 6.39 x 10 6 m from earth's
center.
684 N
2. Suppose that two objects attract each other with a gravitational
force of 40N. If the distance between the two objects is doubled,
what is the new force of attraction between the two objects?
10 N
Journal #4
1/20/2016
• Use the following terms to complete the statements below:
•
•
•
•
•
1.
Potential energy
Kinetic energy
Work
Conservation of energy
Power
Potential energy
is
the energy due to position or stored
energy.
Power
2.
is the rate at which work is done.
3. Conservation of energy means that energy can not be created or
destroyed.
Work
4.
is the energy transferred when a force is
applied over a certain distance.
Kinetic energy
5.
is the energy of motion.
Journal #5
1.
1/21/2016
In what two ways can you increase power?
increase work done or decrease the time
2. Renatta Gass is out with her friends when her car breaks down.
Together they apply a cumulative force of 1080 N to push the car
218 m to the nearest fuel station. Determine the work done on
the car.
235,000 J
3. During practice, Fast Eddie runs up the stairs, elevating his 102 kg
body a vertical distance of 2.29 meters in a time of 1.32 seconds at
a constant speed. Determine the power he generated.
1,730 W
Journal #6
1/22/2016
On a roller coaster,
1.
A
C
Which has the greatest
affect on speed, height or
direction of motion (uphill
or downhill)?
height
B
D
2. How does speed relate to
height?
greater height = greater
final speed at the lowest
height
3. Where do you move the
fastest? Why?
D because it is the lowest
point (PE min = KE max)
Journal #7
1.
2/1/2016
Calculate the speed of an object just as it strikes the ground if it is
dropped from a height of 15 m.
vf = 17 m/s
2. An object is moving 2.5 m/s when it strikes the ground. From
what height was the object dropped?
hi = 0.32 m
3. What happens to the kinetic energy of an object if…
A. the mass of the object is doubled?
kinetic energy doubles
B. the speed of the object is doubled?
kinetic energy quadruples
Journal #8
2/5/2016
• What type of waves are represented in the diagram below?
(a)
(b)
• What is the main difference between these two types of waves?
Transverse waves have perpendicular particle motion and
longitudinal have parallel particle motion to wave direction.
Journal #9
2/8/2016
Water waves in a lake travel 3.4 m in 1.8 s. The period
of oscillation is 1.1 s.
A. What is the speed of the water waves? (HINT: Use
your old equation for speed.)
1.9 m/s
B. What is the frequency of the waves?
0.91 Hz
C. What is the wavelength?
2.1 m
Journal #10
1.
2/9/2016
You observe that a pendulum makes exactly 10 complete back
and forth cycles of motion in 21.8 seconds. Determine the period
of the pendulum.
2.18 s
2. Determine the time delay between a bat’s sending of a pulse and
the return of its reflection from an object located 12.5 m away.
The speed of the sound waves as 345 m/s.
0.0725 s
3. A marine weather station detects waves which are 9.28 meters
long and travel a distance of 50.0 meters in 21.8 seconds.
Determine the speed and the frequency of these waves.
v = 2.29 m/s and f = 0.247 Hz
Journal #11
1.
2/10/2016
Label the following in the diagram below: amplitude, wavelength,
crest, and trough.
2. How many wavelengths are shown in the diagram?
2.5
3. Which variable has the most effect on the period of a pendulum:
length, mass, or amplitude?
length
Journal #12
2/22/2016
• What factor had the biggest effect on the period
of a pendulum?
The length of the string has the greatest effect on
the period of the pendulum. The longer the string,
the longer the period.
• Can you explain why the others had almost no
effect at all?
Because gravity pulls on all objects equally, mass
nor angle have a great effect on the period of a
pendulum.
Journal #13
2/24/2016
1. Sound travels at 5600 m/s through a steel rod. If the
frequency of the wave is 2480 Hz, what is the wavelength
of the wave?
λ = 2.3 m
2. What is the frequency of a sound made by a violin string
with a wavelength of 0.55 m if the wave is traveling at 350
m/s?
f = 640 Hz
3. A wave on the lake has a wavelength of 2 m and has a
frequency of 25 Hz. What is the speed of the wave?
v = 50 m/s
Journal #14
1.
What is the highest
harmonic shown in the
diagram?
7th
2. If the length of the string
is 5 m, what is the
wavelength of the 5th
harmonic?
2m
3. If the fundamental
frequency is 15 Hz, what is
the frequency of the 3 rd
harmonic?
45 Hz
2/26/2016
Journal #15
Use the information provided in the demo and
the diagram to the right to complete the
following questions.
1. How many antinodes appear in the
diagram?
4
2. If the frequency of the first harmonic is
10.0 Hz, what is the approximate
frequency of this wave?
40.0 Hz
3. If the frequency of the wave is increased,
what will happen to the wavelength?
The wavelength will decrease.
2/29/2016
Journal #16
1.
2.
3.
3/4/2016
Of the following electromagnetic waves, which has the longest
wavelength?
A. Microwaves
B. Visible Light
C. Gamma Rays
D. X-rays
Light can have different colors because it can have different…
A. frequencies
B. wavelengths
C. energies
D. All of the above are true.
If an element’s spectral line has a wavelength of 432 nm, what is the
frequency of that element’s spectral line? Approximately what color is
this line?
f = 6.94 x 1014 Hz; approximately blue/violet
Journal #17
3/7/2016
1. The frequency of a beam of light is 4.80 x 10 14 Hz. What
is the wavelength? What is the wavelength in
nanometers?
λ = 6.25 x 10-7 m = 625 nm
2. As the frequency of light increases, what happens to
wavelength?
As frequency increases, wavelength decreases.
3. What type of EM radiation has the highest frequency?
Gamma waves have the highest frequency.
4. What type of EM radiation has the longest wavelength?
Radio waves have the longest wavelength.
Journal #18
1.
3/8/2016
Which color of light is produced by mixing red and blue
light?
A.
white
B.
cyan
C.
yellow
D.
magenta
2. When white light is shined on __________, two primary light
colors are reflected and one primary light color is absorbed.
A.
secondary pigment
B.
primary pigment
C.
both primary and secondary pigments
3. What are the three primary colors of light?
blue, red and green
4. What are the three primary colors of pigment?
cyan, magenta and yellow
Journal #19
3/10/2016
Use the diagrams below to answer questions 1 and 2. The dotted
lines represent the stationary object. The greater the shift, the
faster the motion.
1. Which diagram above shows a star that is moving the fastest
TOWARD the Earth? B
2. Which diagram above shows a star that is moving the
slowest AWAY from the Earth? A
Journal #20
3/11/2016
1. If an object absorbs cyan light and a yellow light source is
shined on the object, what color will it appear?
A. Blue
B. Yellow
C. Red
D. Black
2. An object looks cyan under white light. What color will it
appear if a red light shines on it?
A. Blue
B. Red
C. Green
D. Black
Journal #21
3/14/2016
1. When light falls on a soap bubble or on an oily
film, a spectrum of colors is observed. How is this
spectrum formed?
interference of light waves
2. How would you orient polarizing filters to block
most all of the light from a source?
at a 90 degree angle to one another
3. What is the term that describes when light waves
bend around a barrier?
diffraction
4. Light takes 8.0 minutes to travel from the Sun to
the Earth. How far away is the Sun from the
Earth?
1.4 x 1011 m (about 93 million miles!)
Journal #22
1.
Label the following light
rays as either converging
or diverging.
diverging
2.
3/21/2016
converging
Label the following
diagram with incident
ray, reflected ray, angle
of incidence, angle of
reflection, and normal.
normal
angle of
angle of
incidence reflection
Label the following
diagrams as either
specular or diffuse
reflection.
diffuse
3.
incident ray
specular
reflected ray
Journal #23
Object
Placement/Mirror
Plane Mirror
Between Concave
Mirror and f
At f of Concave
Mirror
Beyond f of
Concave Mirror
Convex Mirror
(anywhere)
3/23/2016
Size of image
compared to size
of object
Real or Virtual
Upright or Inverted
Journal #23
ANSWERS
3/23/2016
Object
Placement/Mirror
Size of image
compared to size
of object
Real or Virtual
Upright or Inverted
Plane Mirror
Same
Virtual
Upright
Between Concave
Mirror and f
Enlarged
Virtual
Upright
At f of Concave
Mirror
No Image
No Image
No Image
Beyond f of
Concave Mirror
Enlarged,
Reduced or Same
Size
Real
Inverted
Convex Mirror
(anywhere)
Reduced
Virtual
Upright
Journal #24
3/24/2016
1. If you know the focal length of a concave mirror, where
should you place an object so that its image is upright and
larger compared to the object?
You should place the object between the focal point (f)
and the mirror.
2. What type of image is formed in the above question?
The image is virtual.
3. Determine the image distance and image height for a 5.00 cm
tall object placed 10.0 cm from a concave mirror having a
focal length of 15.0 cm.
di = -30.0 cm and hi = 15.0 cm
Journal #25
1.
3/25/2016
Refraction occurs when
A. light travels through the boundary of two media that have different
densities.
B. light travels through the boundary of two media that have the same
density.
C. the angle of incidence equals zero.
D. the angle of refraction equals zero.
2. In the figure below, light is traveling from a __________ dense
medium to a __________ dense medium.
A. more, less
B. less, more
Journal #26
3/28/2016
Match the diagrams with the correct image description.
A.
1.
B.
virtual, upright, reduced
B
2.
real, inverted, same size
A
3.
Explain how no image is formed from a lens.
No image is formed when an object is placed at the focal point of a
convex lens.