PHYSICS 11 (Fall 2015)
Exam 3
Elementary Physics
November 16, 2015
Name:
Circle your Recitation:
A01
Myers
(8:30 a.m.)
A03
Yang
(11:40 a.m.)
A04
Pepe
(1:15 p.m.)
A08
Myers
(1:15 p.m.)
A05
Pepe
(2:50 p.m.)
A06
Sanders
(4:25 p.m.)
A07
Sanders
(6:00 p.m.)
A02
Yang
(7:35 p.m.)
INSTRUCTIONS:
For the multiple choice questions on pages 1–2,
you will be graded on the basis of your answer
only. You will get full credit for a correct answer,
zero credit for incorrect answers, zero credit for
choosing multiple answers even if one of them is
the correct response. There is only one correct
answer for each multiple choice question.
SCORE BOX
Page 1
(8)
For the problems on pages 3–5, you must show
your work in the form of a diagram, statement
and/or equation to get full credit, even if you write
down the correct answer. If your answer is incorrect, you will receive partial credit for steps taken
in the direction of the correct solution. So, show
all your work.
Page 2
(16)
Page 3
(14)
Page 4
(14)
No books or notes are permitted in this examination. Writing instruments and a calculator are the
only items that you will need.
Page 5
(12)
Total
(64)
** READ THE QUESTIONS CAREFULLY **
1. A gas is compressed by an isothermal process that decreases its volume by a factor of 2. In this process, the pressure
(a)
(b)
(c)
(d)
increases by a factor of 2.
increases by a factor of more than 2.
does not change.
increases by a factor of less than 2.
ANSWER[
(4)
]
(score)
2. A thermally isolated system is made up of a hot piece of aluminum and a cold piece of copper, with the aluminum
and the copper in thermal contact. The specific heat capacity of aluminum is more than double that of copper. Which
object experiences the greater temperature change during the time the system takes to reach thermal equilibrium?
(a)
(b)
(c)
(d)
(e)
Neither one; both of them experience the same size temperature change.
It is impossible to tell without knowing the masses.
It is impossible to tell without knowing the volumes.
the copper
the aluminum
ANSWER[
αβγδ
(4)
]
(score)
p. 1
page total:
PHYSICS 11 (Fall 2015)
Exam 3
Elementary Physics
November 16, 2015
Name:
3. A 10 kg pail of water is lowered by a rope, starting from rest. When it has descended a distance of 5.0 m, it has a
speed of 5.0 m/s. How much work was done on the pail of water by the rope over this distance?
(a)
(b)
(c)
(d)
(e)
- 96 J
+ 125 J
- 267 J
- 365 J
-463 J
ANSWER[
(4)
]
(score)
4. A boy throws three identical balls off a cliff, each with the same launch speed, but with different launch angles. If air
resistance is negligible, which ball hits the ground with the greatest speed?
(a) A
(b) B
(c) C
(d) They all have the same final speed.
ANSWER[
(4)
]
(score)
5. Two objects constitute an isolated system. In an elastic collision between the two objects, which one of the following
statements is a false statement?
(a)
(b)
(c)
(d)
(e)
The magnitude of the force exerted by each object on the other object is equal.
The total kinetic energy is conserved.
The kinetic energy of each object is the same before and after the collision.
The total momentum is conserved.
The total kinetic energy before the collision is equal to the total kinetic energy after the collision.
ANSWER[
(4)
]
(score)
6. A gas is taken through the cycle shown in the pV diagram in the figure. During one cycle, how much work is done by
the gas?
(a) p0 V0
(b) 2p0 V0
(c) 3p0 V0
(d) 4p0 V0
(e) No work is done because it’s a closed cycle.
ANSWER[
αβγδ
(4)
]
(score)
p. 2
page total:
PHYSICS 11 (Fall 2015)
Exam 3
Elementary Physics
November 16, 2015
Name:
7. A vendor hangs an 9.5 kg sign in front of his shop with a cable
held away from the building by a 3.6 kg uniform pole. The
pole is free to pivot about the end where it touches the wall, as
shown in the drawing. Draw a freebody diagram for the pole
and find
(a) the magnitude of the tension in the cable and
(7)
(score)
(b) the magnitudes of the horizontal and vertical components of the force that the wall exerts on the left end of the
pole.
(7)
(score)
αβγδ
p. 3
page total:
PHYSICS 11 (Fall 2015)
Exam 3
Elementary Physics
November 16, 2015
Name:
8. Suppose you take and hold a deep breath on a chilly day, inhaling 2.5 L of air at −1.5◦ C. Assume that air pressure is
1.0 atm.
(a) How much heat must your body supply to warm the air to your internal body temperature of 37◦ C? Assume that
for air Cp = 29.1 J/(K · mol) as it consists mostly of nitrogen and oxygen.
(7)
(score)
(b) How much does the volume of the air increase as it is warmed?
(7)
(score)
αβγδ
p. 4
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PHYSICS 11 (Fall 2015)
Exam 3
Elementary Physics
November 16, 2015
9. Two hunks of clay slide on a frictionless surface as shown in the figure.
Initially the 3.0 kg mass slides along the x-axis at 1.5 m/s and the 2.0 kg
mass travels at 3.0 m/s in the +y direction. The two hunks of clay stick
together at the origin, then slide away as one. With what speed, and in
what direction do the hunks of clay move after sticking together?
[Hint: What’s the velocity of the center of mass?]
Name:
v
5.0 kg
3.0 kg
1.5 m/s
3.0 m/s
2.0 kg
(12)
(score)
αβγδ
p. 5
page total: