Download PHYSICS 214 TEST 1 12 February 2008

PHYSICS 214
TEST 2
27 March 2008
Sample
Fill in on the OPSCAN sheet:
1) Name
2) Student Identification number
3) Exam number = 02 [there is no section number]
4) YOU MUST SIGN THE OPSCAN SHEET
This test is worth 100 points – it consists of 16 multiple choice problems, each of equal value, 6.25
points.
You may keep your copy of the exam questions, with your answers.
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. Be sure to transfer all your
answers to your OPSCAN sheet. Then, until you go to hand in the OPSCAN sheet, turn it over and
leave it face down to prevent others from seeing your answers.
Only answers on the OPSCAN sheet will be graded – it will not be returned (but you can examine it in
Room 144 at a later date, with help from the secretaries), so be sure you have recorded your answer on
the test paper that you will keep.
A key of 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 and you can use your own crib sheet. 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 cell phones, blackberries, pagers, etc. must be turned off and put out of sight during the exam.
The only items you are allowed are the exam, the OPSCAN sheet, your crib sheet, a pencil, and a
calculator.
1
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 speed
s = d/Δt “
v = d/Δt (vector velocity)
a = Δv/Δt (vector acceleration)
v = v0 + at
d = v0t + ½at2
v2 = v02 + 2ad
d = ½(v + v0)t
F = ma (vector) “N2“
F12 = - F21
“N3“
W = mg
P = 1015
T = 1012
G = 109
M = 106
k = 103
m = 10-3
μ = 10-6
n = 10-9
p = 10-12
f = 10-15
Pressure = Force/Area
Peta
Tera
Giga
Mega
kilo
milli
micro
nano
pico
femto
[N/m2 = Pa = Pascal]
1 Atmosphere = 101.3 kPa = 760mmHg = 33 ft H2O
P = ρgd where d is depth below surface (or height of
a liquid column
Buoyant force = weight of displaced liquid
Circumference = 2R
2
g = 9.8 m/s
G = 6.67  10-11N·m2/kg2
 = 3.14159
 = θ/t = θ/t
e = 1.6x10-19 C
the size of the charge on an electron or a proton
-31
me = 9.1x10 kg
the mass of the electron
mp = 1836 me
the mass of the proton
cH2O= 1 Cal/gm
heat capacity of water
Lf = 80 Cal/gm
latent heat of fusion of water
Lv = 540 Cal/gm
latent heat of vaporization of water
2
DEFINITIONS
a = v2/R
F = mv2/R
F = GM1M2/R2
F = kq1q2/R2
W = Fd
P = W/t = Fv
KE = ½ mv2
PE = mgh
PE = ½ kx2
P = mv
Ft = Pf – Pi = p
Fexternal = 0, p = 0
W = qΔV
P = I ΔV
E = ΔV/d
centripetal acceleration
centripetal force
gravitational force G = 6.61x10-11Nm2/kg2
electrostatic (Coulomb) force k = 9x109 Nm2/C2
work
power
Kinetic energy
potential energy
potential energy
momentum
impulse
momentum conservation
work or energy, electrical
power, electrical
for uniform electric field, where d is distance along
the voltage gradient
ε = (Thot – Tcold)/Thot Carnot efficiency of an ideal heat engine
PV = NkT
Ideal gas law where P,V,T are pressure, volume,
and Kelvin temperature and k is Boltzmann’s constant
2
I = mR
Moment of rotational inertia of a point mass a
distance R from the axis of rotation
Torque = r x F
Torque is product of Force x “Lever arm” distance
to the axis of rotation (the component of distance at right angle to F)
Torque = I α
α
angular acceleration, in radians/s2
KE = 0.5 I ω2
Kinetic energy of rotation of a solid body
2
I = MR
for hoop
2
I = 0.5 MR
for disk
2
I = 0.4 MR
for sphere
2
I = (1/12)ML
for a rod of length L
KEPLER’s Laws
Elliptical orbit sweeps out equal areas in equal time intervals
T2 = r3
for all satellites of a common attracting body, where T is the
period and r is the average radius of the orbit
3
1. A billiard ball (1) moving at 3.5 m/s hits a stationary second billiard ball (2) head-on. The balls
have identical masses and collide elastically. After the collision, which statement is true:
A. (1) recoils backward at 3.5 m/s and (2) moves forward at 3.5 m/s
B. (1) recoils backward at 3.5 m/s and (2) remains at rest
C. (1) is at rest; (2) moves backward at 3.5 m/s
D. (1) is at rest; (2) moves forward at 3.5 m/s
E. Overall, the final kinetic energy is half the initial kinetic energy.
2. A 10 kg mass going 100 m/s collides INELASTICALLY with a stationary 30 kg mass. After
the collision, what is the speed [in m/s] of the two masses?
A. 33.3
B. 25
C. 50
D. 0
E. 10
3. How much Kinetic Energy [in J] is lost during the collision of problem 2.) ? [Be careful to
subtract any residual KE that may be present after the collision.]
A. 5 x 104
B. 1.25 x 104
C. 1.5 x 105
D. 4 x 105
E. 3.75 x 104
4
4. A hoop of mass 30 kg and radius 2 m is spinning (in its own plane, like a bicycle wheel) at 100
rpm. What is its angular velocity
[in radians/s] ?
A 1.67
B. 1.27
C. 62.83
D 10.47
E. 32.0
5. The same hoop is now spun up to 6000 rpm (628.3 rad/s). What is its Kinetic Energy?
A. 18,850 J
B. 37.7 kJ
C. 47.4 MJ
D. 0.540 GJ
E. 23.7 MJ
5
6. You dive 99 feet deep in a fresh-water lake. What is the TOTAL pressure on your body?
A. 1 Atmosphere
B. 3 Atm.
C. 4 Atm.
D. 5 Atm.
E. 6 Atm.
7. Your mass is 75 kg. You neither sink nor float upwards. What is the buoyant force of the water on
you?
A. 75 N
B. 735 N
C. 0
D. 98 N
E. 980 N
6
8. You want to walk along a glass ceiling using suction cups. You weigh 588 N. What is the smallest
area [in m2] of a single suction cup that will just support your weight? [1 Atm. = 101.3 kPa]
A. 0.0058
B. 0.10
C. 5.88
D. 0.936
E.
0.0010
9. You go skiing in Banff. The thermometer registers -30oCelsius. What is the temperature on the
Farenheit scale (oF)?
A. -40
B. -25
C. -30
D.
-22
E. -17
7
10. How many grams of liquid water at 100oC must be added to 1000 grams of Ice which
is at 0oC, in order to just melt the ice and have ALL the water be at 0oC? The heat of
fusion of Ice is 80 grams/Calorie and you should know the heat capacity of one gram of
water (it defines the Calorie!)
A. 1000 g
B. 800 g
C. 540 g
D. 1200 g
E. 5400 g
11. What is the theoretical maximum efficiency (the Carnot efficiency) of a turbine that
operates with hot gas at 1000K and releases heat to the environment at 300K?
A. 100%
B. 30%
C. 70%
D. 50%
E. 42.86%
8
12. What is the electrical force between two protons separated by 10-10m?
A. 14.4 N
B. 2.3 x 10-8 N C. 2.3 x 10-28 N
D. 2.56x10-38 N
E. 6.4x10-8 N
13. Two wide parallel metal plates which are 5 cm apart, are hooked to a 300 V battery.
What is the magnitude of the electric field between the two plates?
A. 300 V/m
B. 3 kV/m
C. 6 kV/m
D. 15 kV/m
E. 15 V/m
9
14. The plates are now disconnected from the battery, and then pulled apart to a
separation of 15 cm. Since the field is caused by the charges on the plates, which
do not change, now what is the potential difference between the plates?
A. 100 V
B. 300 V
C. 900 V
D. 33 V
E. 2700 V
15. Two positive electric charges, +4mC and +1mC are located on the x-asix at x = 0
and x = 3 m, respectively. Where is the Electric field equal to zero? Draw a
picture and point your vectors carefully.
A. x = 0
B. x = 1 m
C. x= 2 m
D. x= 4m
E. someplace NOT on the x-axis
10
16.
A balloon with volume 0.35 m3 is submerged in Mercury to a depth of 7.60 m
(that’s 7600 mm, or ten times the column of mercury in a barometer at sea level).
What is the new volume of the balloon, if the Temperature is kept constant?
A. 3.5 m3
B. 350 m3
C. 0.035 m3
D. 0.00035 m3
E. 0.76 m3
11