An elastic collision between two particles,one of mass M and the other of mass 4M.
Which particle feels a greater force?
Justify your answer mathematically

Imagine your class has been hired to secure the network of a relatively small public school system. The system's network(s) includes administrative offices, classroom computers, Web servers, e-mail servers, and other typical features. Your class decides that multiple layers of firewall protection are required. As a group, discuss the firewall options described in this chapter and decide which ones to use. Where would you place each type of firewall, and why?

Linearly polarized light that is oriented along the x-axis and has intensity I₀ is incident on a linear polarizer (LP1) with transmission axis oriented at an angle θ₁=15° clockwise with respect to the x axis. The light then passes through a second linear polarizer (LP2) with transmission axis oriented at an angle θ₂ = 45° counterclockwise relative to the x axis as shown before passing through a quarter wave plate. The fast axis of the quarter wave plate is aligned with the y-axis.

1)

What is the intensity of the light after the second linear polarizer (LP2) but before the quarter wave plate?

I ₂ = 0.25 I₀

I ₂ = 0.467 I₀

I ₂ = 0.75 I₀

I ₂ = 0.233 I₀

I ₂ = 0.7 I₀

2)

What is the polarization after the light passes through the quarter wave plate?

Linearly polarized along θ₂

Left circularly polarized

Right circularly polarized

3)

Keeping the linear polarizers and quarter wave plate exactly the same, the incident light is now changed to be unpolarized as shown below. What is the intensity of light measured after the quarter wave plate(IQWPIQWP)?

IQWP=IQWP= 0.125 I0I0

IQWP=IQWP= 0.233 I0I0

IQWP=IQWP= 0.5 I0I0

IQWP=IQWP= 0.0583 I0I0

IQWP=IQWP= 0.467 I0

How far apart are an object and an image formed by an 75 −cm -focal-length converging lens if the image is 3.40 × larger than the object and is real? Express your answer using two significant figures. do+di = cm

1. The photoelectric effect experiment is often carried out by using a mercury light source to illuminate a particular surface. The emission spectrum of mercury has strong lines at wavelengths of 365.5 nm (ultraviolet), 404.7 nm (violet), 435.8 nm (blue), and 546.1 nm (green). The light can be passed through a diffraction grating to separate the light into these different wavelengths. Assume that photons of all these wavelengths have enough energy to overcome the work function of the surface. If the maximum kinetic energy of the emitted electrons is 1.26 eV when the green light illuminates the surface, what will the maximum kinetic energy of the emitted electrons be when the blue light illuminates the surface?

2. Two energy levels in a particular atom are at energies of −23.4 eV and −27.3 eV. When an electron makes a transition from one of these levels to the other, a photon is emitted. Calculate the wavelength of the photon. nm

A piece of ice having a mass of 2 kg and an initial temperature of −272 ℃ (very cold!) is dropped into a container of water at 25 °C. Remember that: The specific heat of water is ?? = 4186 ? ??℃ , The specific heat of ice is 2100 ? ??℃ The latent heat of fusion for water is ?? = 333000 ? ?? .

a. Very soon after the piece of ice was dropped into the water, all the water froze into ice at 0 ℃. What was the mass of the water the container?

?? = ____________ kg

b. Suppose now we drop that same ice cube (same mass same temperature) into a container that has 1 kg of water at 25 °C. All the water will freeze and become ice. What is the final temperature of the ice?

? = _____________ ℃

Part A
How many conduction electrons are there in a 4.50 mm diameter gold wire that is 30.0 cm long?

Part B
How far must the sea of electrons in the wire move to deliver -24.0 nC of charge to an electrode?

Express your answer with the appropriate units.

1. Consider placing two point charges on an x-y plane, the first charge, q1, at (x1, y1), and the second charge , q2, at (x2, y2).

2. Derive an expression for the electric potential and field at any arbitrary point (x, y) in terms of q1, q2, x1, x2, y1 and y2.

3. Choose some reasonable values for q1, q2, x1, x2, y1 and y2 and make a rough sketch of what you expect the electric potential/field to look like. Your picture doesn’t necessarily have to be correct, but you should include some justification for why your sketch looks the way it does. 4. Use SageMath to draw the exact electric potential and field using the expression derived above. Below is an example. x, y = var("x y") g = Graphics() g += contour_plot(1.5 + 0.2*x*y, (x, -4, 4), (y, -4, 4), fill=False, cmap="jet", labels=True, contours=[0, 1, 2, 3, 4], label_fontsize=14) g += plot_vector_field((y/2, -x/2) , (x, -4, 4), (y, -4, 4)) g.show() Your final result should look something like the figure below. Note how you can clearly see the two point charges at (1, 2) and (2, 1.5).

Please answer based on nuclear activity and please identify the terms for question 1, part a and part b. Please answer the second part of the question, question 2 in an answer that matches the question correctly. I am re-posting these as they were answered incorrectly last time.

1. What terms identify

a) a radioactive material that, upon decay, results in another radioactive material?

b) the resulting radioactive material?

&

2. Under what conditions is secular equilibrium reached between the daughter and parent?

Two charged proteins P1 and P2 are located at positions (1m,1m) and (-1m,1m) respectively on a Cartesian coordinate system. They have charges of 1.0 nC and -1.0 nV respectively. A key enzyme E1 which regulates an important biochemical pathway, is localed at the origin of the coordinate system.

1. compute the electrical potential V at the position of E1
2. Draw a vector diagram for the electrical field vector ETOT, at the position of E1.
3. show, or argue that the y component of the electrical field vector ETOT,Y at the position of E1, is equal to zero
4. Compute the electrical field vector ETOT, at the position of E1. Hint: ETOT is a vector!

A copper flask (??????? = 51 × 10−6 1 ℃ ) with a volume of 500 cm3 contains 490 cm3 of olive oil (???? = 0.68 × 10−3 1 ℃ ) at a temperature ?0 = 20 ℃.

a. To what temperature must the flask and the oil be heated so that the flask will be completely filled?

? = _________________ ℃

b. Calculate the volume of the copper flask when the temperature is equal to that you calculated in part (a).

??? = _________________ cm3

c. Calculate the volume of the olive oil when the temperature is equal to that you calculated in part (a).

???? = _________________ cm

Rotating Nucleus

According to a crude model, the ⁷Li nucleus is a uniform solid sphere of mass 1.16×10^-26kg and radius 2.30×10^-15m which spins about its diameter. The angular momentum of this spinning lithium nucleus is 1.58×10^-34J ·s. According to this model, what is the angular velocity of the lithium nucleus?
6.44×10²¹ rad/s

What is the linear velocity of a point on its equator? (Aside: Compare your result to the speed of light, c = 3.00×10⁸m/s)
1.48×10⁷ m/s

What is the rotational kinetic energy?
5.09×10^-13 J

What is the ratio of the rotational kinetic energy to the relativistic rest-mass energy? (Note: The relativistic rest-mass energy of any particle is given by Einstein's famous equation E = m ·c², where c = 2.9979×10⁸m/s is the speed of light.)

An airplane propels itself eastward with speed v. A crosswind with speed u is directed at an angle θ (0 < θ < π) north of east. What is the distance travelled by the plane after a time t?

A certain elastic string has a spring constant of 18n/m, a relaxed length of 3 meters, and a mass of 20 grams. A 500 g mass is hung on a string and given a kinetic energy of 2J. While the mass is in oscillating, the string can be plucked and it will produce a sound. What is the highest and lowest frequency of sound which can be produced by plucking the string in this situation.