General Physics: Electricity and Magnetism SCHD W/PHYS 212P
PHYS 212L

Fall 2015
Physics 212 Test 2 Spring 2015 Name 1
Instructions:
1. Please DO NOT open this packet or begin the test until you are told to do so. Read through the instructions
completely.
‘ 2. There are 100 possible points on this test, plus an extra credit problem wo
17.1. Model: For a gas, the thermal energy is the total kinetic energy of the moving molecules. That is, Eth =
Kmicro. Solve: The number of atoms is
N=
M 0.0020 kg = = 3.01 10 23 m 6.64 10 27 kg
Because helium atoms have an atomic mass number A
16.1. Solve: The mass of lead mPb = Pb VPb = (11,300 kg m 3 )(2.0 m 3 ) = 22,600 kg . For water to have the
same mass its volume must be
Vwater =
mwater 22,600 kg = = 22.6 m 3 water 1000 kg m 3
16.2. Solve: The volume of the uranium nucleus is
V
15.1. Solve: The density of the liquid is
=
m 0.120 kg 0.120 kg = = = 1200 kg m 3 V 100 mL 100 10 3 10 3 m 3
Assess: The liquid's density is more than that of water (1000 kg/m3) and is a reasonable number.
15.2. Solve: The volume of the helium
14.1. Solve: The frequency generated by a guitar string is 440 Hz. The period is the inverse of the frequency, hence
T= 1 1 = = 2.27 10 3 s = 2.27 ms f 440 Hz
14.2. Solve: Your pulse or heart beat is 75 beats per minute. The frequency of your hear
13.1. Model: The crankshaft is a rotating rigid body.
Solve: The crankshaft at t = 0 s has an angular velocity of 250 rad/s. It gradually slows down to 50 rad/s in 2 s, maintains a constant angular velocity for 2 s until t = 4 s, and then speeds up
12.1.
Solve: (b)
Model: Model the sun (s), the earth (e), and the moon (m) as spherical. (a)
Fs on e =
Gms me (6.67 10 11 N m 2 / kg 2 )(1.99 10 30 kg)(5.98 10 24 kg) = 3.53 10 22 N = (1.50 1011 m ) 2 rs2 e 
Fm on e =
GMm Me (6.67 10 1
11.1. Visualize:r Please refer to Figure Ex11.1. r
Solve: (b) (c)
(a) A B = AB cos = ( 4)(5)cos 40 = 15.3. r r C D = CD cos = (2)( 4)cos120 = 4.0. r r E F = EF cos = (3)( 4)cos 90 = 0.
11.2. Visualize:r Please refer to Figure Ex11.2. r
Solve
10.1. Model: We will use the particle model for the bullet (B) and the bowling ball (BB).
Visualize:
Solve:
For the bullet,
KB =
For the bowling ball,
1 1 2 mB vB = (0.01 kg)(500 m /s) 2 = 1250 J 2 2 1 1 2 mBB vBB = (10 kg)(10 m / s) 2 = 500 J 2
Solve: (a) The momentum p = mv = (1500 kg)(10 m /s) = 1.5 10 4 kg m /s . (b) The momentum p = mv = (0.2 kg)( 40 m /s) = 8.0 kg m /s .
9.1. Model: Model the car and the baseball as particles.
9.2. Model: Model the bicycle and its rider as a particl
8.1. Visualize:
Solve: Figure (i) shows a weightlifter (WL) holding a heavy barbell (BB) across his shoulders. He is standing on a rough surface (S) that is a part of the earth (E). We distinguish between the surface (S), which exerts a contact forc
7.1. Solve: (a) From t = 0 s to t = 1 s the particle rotates clockwise from the angular position +4 rad to 2 rad. Therefore, = 2  ( +4 ) = 6 rad in one sec, or = 6 rad s . From t = 1 s to t = 2 s, = 0 rad/s. From t = 2 s to t = 4 s the partic
18.1. Solve: We can use the idealgas law in the form pV = NkBT to determine the Loschmidt number (N/V):
1.013 10 5 Pa N p = 2.69 10 25 m 3 = = V kB T (1.38 10 23 J K )(273 K )
(
)
18.2. Solve: Nitrogen is a diatomic molecule, so r 1.0 101
19.1. Model: The heat engine follows a closed cycle, starting and ending in the original state. The cycle
consists of three individual processes. Visualize: Please refer to Figure Ex19.1. Solve: (a) The work done by the heat engine per cycle is the a
General Physics: Electricity and Magnetism SCHD W/PHYS 212P
PHYS 212L

Fall 2015
Physics 212 Quiz 63 Spring 2015 Name K E i
The batteries, wires and bulbs in each circuit below are identical and ideal.
Case 1: Case 2:
1a. In case 1 above, bulbs b and c are wired in parallel (1 point)
b. Rank the brightness of each bulb in the circui
General Physics: Electricity and Magnetism SCHD W/PHYS 212P
PHYS 212L

Fall 2015
Physics 212 Spring 2015 Quiz 1A Name I
1
4176:,
F:"“‘” E=—~ Fa,.q=qE K: =9.Oxi09Nm2/C2 e=1.602x10"9c n=ur9
r2 r2
1. A positively charged electroscope is has separated leaves.
a) Which statement correctly describes how the electroscope became charged?
General Physics: Electricity and Magnetism SCHD W/PHYS 212P
PHYS 212L

Fall 2015
Information for Test 4
Content: Test 4 will contain material from chapters 32 and 33, but you will be expected to apply
material from previous chapters as well. You are allowed to bring a 4 x 6 note cord, both sides.
Chapter 32
Reading: All sections, but
valuatetheintegral
.
A. B. C. D. E.
1/1 C C
PointsEarned: CorrectAnswer: YourResponse: 2.
Evaluate
.
A. B. C.
D. E.
0/1 B A
PointsEarned: CorrectAnswer: YourResponse: 3.
Evaluate
.
A. B. C. D. E.
PointsEarned: 0/1 B E 4. Evaluate . CorrectAnswer: YourResp
Faradays Law, Inductance, and RL Circuits
NAME: NAME: NAME: RECITATION SECTION: INSTRUCTOR: DATE: _ _ _ _ _ _
This activity is based on the following concepts: Faraday's Law of Induction: If the magnetic flux B through a closed loop C changes with time, a
5.1.
Model: We can assume that the ring is a single massless particle in static equilibrium. Visualize:
Solve:
Written in component form, Newton's first law is
( Fnet ) x = Fx = T1x + T2 x + T3 x = 0 N
T1 x =  T1
T1y = 0 N Using Newton's first l
4.1. Solve: A force is basically a push or a pull on an object. There are five basic characteristics of forces. (i) A force has an agent that is the direct and immediate source of the push or pull. (ii) Most forces are contact forces that occur at a
3.1. Solve: (a) If one component of the vector is zero, then the other component must not be zero (unless the whole vector is zero). Thus the magnitude of the vector will be the value of the other component. For example, if Ax = 0 m and Ay = 5 m, the
2.1.
Solve:
Model: The car is represented by the particle model as a dot. (a) Time t (s) Position x (m) 0 1200 1 975 2 825 3 750 4 700 5 650 6 600 7 500 8 300 9 0
(b)
2.2. Solve:
Diagram (a) (b) (c)
Position Negative Negative Positive
Velocity
1.1.
Solve:
1.2.
Solve:
Solve: (a) The basic idea of the particle model is that we will treat an object as if all its mass is concentrated into a single point. The size and shape of the object will not be considered. This is a reasonable approxim
6.1. Model: We will assume motion under constantacceleration kinematics in a plane.
Visualize:
Instead of working with the components of position, velocity, and acceleration in the x and y directions, we will use the kinematic equations in vector f
Nikola Tesla (18561943)
Magnetic Fields I
Electric charges create electric fields Electric fields lead to forces on electric charges Moving electric charges create magnetic fields Magnetic fields lead to forces on moving electric charges Electric
Alessandro Volta (17451827)
Last Time
E=0 in a conductor, and E is to conducting surfaces Gauss' Law can be used to determine E when E is constant and perpendicular to a Gaussian surface (imaginary).
The Electric Potential
Today
This lecture:
Carl Friedrich Gauss 17771855
Last Time
nothing moves Electric Flux Amount of electric field crossing a surface Gauss' Law
Gauss' Law II
I have changed my office hour on Friday to 45.
=
Closed Surface
r r Q E dA = enclosed 0
.. and appl