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Physics 214
Practice exam 2 A
Fill in on the OPSCAN sheet:
1) Name
2) Student identification number
3) Exam number as 02
4) Sign the OPSCAN sheet
Important: This test consists of 15 multiple choice problems, each worth 6.667 points.
Instructions: For each problem, choose the one answer that is correct or most nearly correct. Make a small
mark, for your eyes only, near the letter of your choice. After you finish and check all the multiple-choice
problems, transfer your answers to the computer sheet. Then, until you hand in the computer sheet, turn the
sheet over and leave it face down.
Only answers on the computer answer sheet will be graded. As your OPSCAN answer sheet will not be
returned, record the answers on the test paper that you will keep.
The correct answers will be displayed on the course web page, and you can find your score for this exam on
CHIP.
This is a closed book exam, but a crib sheet is provided. You may also use a calculator.
Any form of cheating will result in severe penalties, which will include a score of zero for this exam and may
result in a grade of F for the course and referral to the Dean of Students.
All electronic devices must be securely put out of sight and may not be touched during the exam.
All cell phones and pagers must be turned off.
The only items you are allowed are the exam, the opscan sheet, a pencil and a calculator
FORMULAE AND CONSTANTS
Conversion Factors
1 inch = 2.54 cm
1 ft = 30.5 cm
1 m = 3.281 ft
1 km = 0.621 miles
1 mile = 5280 ft
1 nautical mile = 1.1508 miles
1 kg = 2.205 lbs (where g = 9.8 m/s2)
Equations
s = d/t
s = d/Δt
v = d/Δt (vector)
a = Δv/Δt (vector)
v = v0 + at
d = v0t + ½at2
d = ½(v + v0)t
F = ma (vector)
W = mg
average speed
instantaneous speed
instantaneous velocity
acceleration
force
weight
a = v2/R
F = mv2/R
F = GM1M2/R2
W = Fd
P = W/t
KE = ½ mv2
PE = mgh
PE = ½ kx2
P = mv
FΔt = Pf – Pi = Δp
Fexternal = 0, Δp = 0
centripetal acceleration
centripetal force
gravitational force
work
power
Kinetic energy
potential energy
potential energy
momentum
impulse
momentum conservation
Circumference = 2πR
g = 9.8 m/s2
G = 6.67 × 10-11N·m2/kg2
π = 3.14159
ω = θ/t = Δθ/Δt
α = Δω/t
ω = ω0t + αt
θ = ω0t + ½ αt2
Torque = Fℓ = τ
L = Iω
τ = Iα
τexternal = 0,
P = F/A (pressure)
P = ρgh (liquid)
ρ = m/V kg/m3
PA = 1.01 x 105 Pas
Buoyant force = weight
of liquid displaced
∆U = Q – W (internal energy
PV = NkT ( for a gas)
ε
= W/QH (engine efficiency)
ε
= (TH – TC)/TH (Carnot
efficiency)
TC = 5/9(TF-32) TF = (9/5)TC +32 (0°C
= 273.2°K)
1 calorie = 4.186 joules
Q = mc∆T
c = 1 cal/gm/°C for water 0.49 cal/gm/°C for ice
Latent heat of vaporization for water = 540 cal/gm (heat required
to turn water to steam at 100 0C)
Latent heat of fusion for water = 80 cal/gm
(heat required to melt ice at 0oC )
qe = -1.6 x 10-19C
I = q/t amps
F = k q1q2/r2
R = ∆V/I ohms
k = 9 x 109N.m2/C2
R = R1 + R2 + R3 (series)
E = F/q (electric field)
1/R = 1/R1+1/R2+1/R3 (parallel)
V = ∆PE/q (potential
P =
difference)
∆V = Ed (uniform E)
εI
= I2R watts (power)
Name: __________________________ Date: _____________
1. A metal sphere has a positive electric charge. A small piece of paper is initially
attracted to it. This can be explained by:
A) The paper must have no net charge on it
B) The paper must be positively charged.
C) The paper must be negatively charged.
D) The paper might be negatively charged, or it might have no net charge on it.
2. How much heat in calories must be added to 54 g of water at an initial temperature of
56°C to completely convert the 54 g water at an initial temperature of 56°C to steam at
100°C?
A) 29160
B) 31536
C) 8648
D) 2376
E) 15632
3. A 20-kg child runs at 4.0 m/s and jumps onto a shopping cart, which has a mass of 30
kg.
Assuming the child rides on the cart after the collision, the speed of the child and
shopping cart,just after the child jumps on, is
A) 1.4m/s
B) 3.6m/s
C) 1.6 m/s.
D) 2.7 m/s.
E) 4.0 m/s.
4. A merry-go-round, having a radius of 2.0 m, is set in motion by students applying a
force of 500 N tangential to the rim of the wheel. The merry-go-round reaches a
rotational velocity of 2.0 rad/s after 10 seconds, starting from rest. The rotational inertia
of the merry-go-round is
A) 5.0 x 103 kg m2
B) 5.0 x 105 kg m2
C) 1.0 x 104 kg m2
D) 5.0 x 104 kg m2
E) 1.0 x 105 kg m2
5. A plank is balanced about a pivot point (seesaw). A mother with a mass of 60kg sits
75cm from the pivot point. How far from the pivot point in meters does her child with a
mass of 25kg have to sit to balance the seesaw?
A) 3.4
B) 1.4
C) 3.2
D) 1.8
E) 2.4
6. An engine is usually a device where heat is generated by burning some kind of fuel, and
this heat is then converted into work. Under ideal conditions, how much of the heat
energy can be converted into work?
A) None of it.
B) Some of it, but never all of it.
C) All of it.
7. A test charge of +5x10-6C experiences forces from two other nearby charges: a force of
10N due east and a force of 7N due west. What is the magnitude of the electric field at
the location of the test charge in N/C?
A) 6 x 105
B) 15 x 10-6
C) 4 x 10-5
D) 3 x 103
E) 34 x 105
8. A 60kg person is travelling in a car at 30m/s which crashes and comes to a stop in 0.4
seconds and in the same time the airbag brings the person to a stop. What is the ratio of
the force supplied by the airbag to the persons weight?
A) 8.67
B) 1.00
C) 5.35
D) 7.65
E) 2.33
9. A rock with volume of 0.8m3 is fully submerged in water having a density of water is
1000 kg/m3. What is the buoyant force acting on the rock in Newtons?
A) 4220
B) 7840
C) 800
D) 1200
E) 5650
10. The electric potential increases from 82 V to 586 V from the bottom to the top plate of a
capacitor. What is the magnitude of the change in potential energy in joules of a
-2 x 10-4 C as it is moved from the bottom to the top plate?
A) 212 x 103
B) 0.8
C) 252 x 104
D) 168
E) 0.1
11. A 115.8-lb woman puts all her weight on one heel of her high-heel shoes. The heel has
an area of 0.3 in2. What is the pressure that her heel exerts on the ground in pounds per
square inch (psi)?
A) 3.55
B) 319.4
C) 386.0
D) 34.75
E) 3782.8
12.
A)
B)
C)
A cube made of solid wood floats when put into water. This means that
the cube weighs more than an equal volume of water.
the cube weighs less than an equal volume of water.
the cube weighs the same as an equal volume of water.
13. The temperature on a hot summer day is 97°F. What is the temperature in degrees
Celsius?
A) 36.1
B) 33.3
C) 48.6
D) 53.9
E) 25.2
14. A figure skater is spinning with her arms extended. She now pulls her arms close to her
body. What happens?
A) Her angular momentum decreases.
B) Her moment of inertia decreases.
C) Her kinetic energy does not change
D) Her moment of inertia increases.
E) Her angular momentum increases.
15. A beaker containing 318 g of water has 1153 J of work done on it by stirring and 266
cal of heat added to it from a hot plate. What is the temperature change of the water in
°C?
A) 8.33
B) 1.7
C) 0.8
D) 7.22
E) 4.46
Answer Key
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