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Physics1101

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... heat must be removed from 456 g of water at 25.0eC to change ... A 25.0-g string is stretched with a tension of 43.0 N between two fixed points 12.0 m apart. ... – PowerPoint PPT presentation

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Title: Physics1101

1
Physics1101

Multiple choice

MULTIPLE CHOICE. Choose the one alternative that
best completes the statement or answers the
question.
You are driving along a highway at 25 m/s when
you hear the siren of an emergency vehicle
traveling in the opposite direction on the other
side of the highway. When the vehicle is
approaching you, you hear the frequency of the
siren as 2300 Hz, but when it is past you the
frequency becomes 1600 Hz. What is the speed of
the vehicle? The speed of sound in air is 343
m/s.
A) 30 m/s B) 41 m/s C)
32 m/s D) 37 m/s

Two unknowns
Solve for f
Substitute in equation 2 into equation 1
3

A camper is about to drink his morning coffee. He
pours 400 grams of coffee, initially at 75.0eC,
into a 250-g aluminum cup, initially at 16.0eC.
What is the equilibrium temperature of the
coffee-cup system, assuming no heat is lost to
the surroundings? The specific heat of aluminum
is 900 J/(kg\'97K).
A) 71.0eC B) 68.0eC C) 65.0eC D)
62.0eC

If you add 1.73 MJ of heat to 700 g of water at
70eC, what is the final temperature of the
steam? The latent heat of vaporization of water
is 22.6 þ 10 to power of (exponent) J/kg. The
specific heat of steam is 2010 J/(kg K).
A) 123eC B) 143eC C) 100eC D)
147eC

First find how many joules it take to bring
water to boil.
Subtract this from the heat being supplied.
Remember the heat being supplied is 1730000J
Now use this to find the final temperature of the
steam
Now solve for tf
5

The intensity level of a power mower at a
distance of 1.0 m is 100 dB. You wake up one
morning to find that four of your neighbors are
mowing their lawn 20 m from your open bedroom
window. What is the intensity level in your
bedroom?
A) 400 dB B) 50 dB C) 80 dB
D) 104 dB

Note that the intensity level is in db. So you
will have to change it to W/m2
Io1 10-12 W/m2.
Now you will have to change it back to db.
6

A 42.0-g block of ice at -15.0eC is dropped into
a calorimeter containing water at 15.0eC. When
equilibrium is reached, the final temperature is
8.0eC. How much water did the calorimeter contain
initially? The specific heat of ice is 2090 J/(kg
K) and the latent heat of fusion of water is 33.5
104 J/kg.
A) 546 g B) 405 g C) 634 g
D) 302 g

Two strings of identical mass per unit length are
stretched with the same tension with their ends
fixed, but one string is 0.33 cm longer than the
other. Waves on these strings propagate at 36.4
m/s. The fundamental frequency of the shorter
string is 258 Hz. What is the beat frequency when
each string is vibrating at its fundamental
frequency?
A) 12.7 Hz B) 12.0 Hz C) 11.3
Hz D) 11.5 Hz

A 400-g piece of metal at 130 oC is dropped into
a cup containing 450 g of water at 15.0 oC. The
final temperature of the system is 40.0 oC. What
is the specific heat of the metal, assuming no
heat is exchanged with the surroundings or the
cup?
A) 3420 J/(kg.K) B) 1310 J/(kg.K)
C) 2830 J/(kg.K) D) 3780 J/(kg.K)

The speed of sound through the ground is about
6.0 km/s while the speed of sound in air is 343
m/s. A very powerful explosion occurs some
distance away and you feel the ground vibrate 60
seconds before you hear the sound of the
explosion. How far away is the explosion?
A) 20 km B) 25 km C) 22 km D)
27 km

The wave speed in an aluminum wire with a radius
of 1.00 mm is 120 m/s. What is the tension in the
wire? The density of aluminum is 2.70 x 103
kg/m3.
A) 112 N B) 122 N C) 427 N
D) 134 N

Note to solve this problem it will take a little
rearranging of various formulas, so pay attention
to the algebra.
M?V
VAL
The lengths will cancel here and Apr2.
Square both sides to get rid of the root sign.
11

How much heat must be removed from 456 g of water
at 25.0eC to change it into ice at -10.0eC? The
specific heat of ice is 2090 J/(kg K) and the
latent heat of fusion of water is 33.5 þ 10 to
power of (exponent) J/kg.
A) 153 kJ B) 210 kJ C) 57.3 kJ
D) 47.7 kJ

A 25.0-g string is stretched with a tension of
43.0 N between two fixed points 12.0 m apart.
What is the frequency of the second harmonic?
12.0 Hz B) 6.00 Hz C) 24.0 Hz D) 18.0
Hz

A harmonic wave travels with a speed of 200 m/s
and has a wavelength of 0.800 m. What is the
frequency of the wave?
250 Hz B) 125 Hz C) 40.0 Hz D) 80.0 Hz

One of the harmonics of a column of air closed at
one end has a frequency of 448 Hz and the next
higher harmonic has a frequency of 576 Hz. What
is the fundamental frequency of the air column?
256 Hz B) 64 Hz C) 32 Hz D) 128 Hz

Remember that for a closed pipe at one end it has
odd harmonics
Create 2 equations
Solve for f1 for both equations
Substitute one equation into the other and Solve
for n.
Now put this into both equations to solve for f1

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