A 20 g ball of clay traveling east at 3.5 m/s collides with a 35 g ball of clay traveling north at 2.0 m/s .

Part A What is the movement direction of the resulting 55 g blob of clay?

Express your answer in degrees north of east. θ θ =

Part B What is the speed of the resulting 55 g blob of clay?

Shlomo Sternberg (math professor at Harvard) wrote a book called "Group theory and physics". On p156 (link) there's a strange offhand comment:

"Experiments done in 1964 by Fitch and Cronin seem to indicate that CP is not conserved. I do not fully understand the issues involved in the correct interpretation of this experiment, which clearly shows that CP and CPT are not both conserved. It follows from the locality axioms, that quantum field theory implies that CPT is a symmetry of nature, and hence that CP is violated in the Fitch-Cronin experiment. But other, group theoretical, hypotheses might favor CP. I have my own views on the subject, which I will not expand on in this book."

I cannot find any other publication where Prof. Sternberg elaborated his views on this. But he obviously suspects that CP is an exact symmetry while CPT is not.

So the question is: (1) Does the Fitch-Cronin experiment (or any other) disprove CP? Or does it only "show that CP and CPT are not both conserved"? (2) If the latter, is it remotely plausible that CPT is false? (How universal is the CPT theorem? Does it hold even in string theory?)

adv

The International Space Station (ISS) had many of its components launched by the Space Shuttle. After the Space Shuttle's retirement, what is the proposed launch vehicle for new ISS sections?

I'm interested in doing simulations with large numbers of particles and need a good n-body code. Are there any out there in the public domain that are open-source and what are their strengths and weaknesses. I'm interested in all types of codes, ones that can be run on a multi-core desktop for basic simulations and also ones that can be run on large parallel clusters (I have access to both).

For each entry please provide a link and a brief summary of the nature of the code and strengths of the software. The goal here is to provide a reference list for those interested in the topic

Not much more to add. Why pick one over another?

A vessel contains 10 kg of water with a quality of 0.85 at a pressure of

a) 150 kPa

b) 200 kPa

c) 2 MPa

For the above pressures, determine the volume of liquid and volume of vapor. Also, what is the temperature of mixture.

An object lies 12 cm to the left of a thin double-convex lens of equal radii 4.8 cm and n=1.6. The lens forms an image at I1, on the right of the lens. It is desired that the image should be at I2, 2cm to the right of I1. To obtain this result, a thin lens of focal length +/- 12 cm is placed between the first lens and I1. Deduce what kind of lens is needed, and find the distance of the second lens from the first. Draw a ray diagram.

A downward force is applied to a wedge with a 40deg tip. The wedge separates two blocks (which have matching 20deg angles, so 40deg included, matching the wedge's profile) which face opposite directions from one another. Behind each block is a compression spring with a solid wall (cannot move) behind it.

What would the free body diagram look like for each block as well as the force balance equation for the system?

thank you!

speed on an electron

Two stationary positive point charges, charge 1 of magnitude 3.25nC and charge 2 of magnitude 1.75nC , are separated by a distance of 42.0cm . An electron is released from rest at the point midway between the two charges, and it moves along the line connecting the two charges.

What is the speed vfinal of the electron when it is 10.0cm from charge 1?

Express your answer in meters per second.

As you ride on a Ferris wheel, your apparent weight is different at the top than at the bottom.

1-Explain this phenomenon.

2-Calculate your apparent weight at the bottom of the Ferris wheel,given that the radius of the wheel is 7.2m, it completes one revolution every 28s, and your mass is 60kg.

3-Suppose the Ferris wheel were rotating just fast enough to make you feel weightless at the top. How many seconds would it take if to complete one revolution? [Assume the radius of the wheel is still 7.2m.]

A rocket car is constrained to move on an elliptical track (semi major axis p and semi minor axis q). The car is moving at a constant speed mu. Determine the acceleration of the car is meters per second squared. P = 4 km, q = 2km and mu = 360 km/hr.

Three identical point charges each of charge q are located at the vertices of an equilateral triangle as in the figure shown below. The distance from the center of the triangle to each vertex is a. (a) Show that the electric field at the center of the triangle is zero. (Submit a file with a maximum size of 1 MB.) This answer has not been graded yet. (b) Find a symbolic expression for the electric potential at the center of the triangle. (Use any variable or symbol stated above along with the following as necessary: ke for the Coulomb's constant.) V = (c) Give a physical explanation of the fact that the electric potential is not zero, yet the electric field is zero at the center.

A 13-

A uniform disc of charge has a total charge of 7.00x10-12 C and a radius of 10.0 cm.

A) Find the electric field at a point along its axis 20.0 cm from its center. (1.33 N/C away*)

B) Show that the electric field drops as 1/x2 as x approaches ?. Hint: remember that (1+x)n ~ 1+nx if x<<1)

Two capacitors are connected in series. Let 3.30?F be the capacitance of first capacitor, 5.00?Fthe capacitance of the second capacitor, and Vab = 60.0V the potential difference across the system.

A)Calculate the charge on each capacitor (Q1 AND Q2)

B)Calculate the potential difference across each capacitor.(Q1 AND Q2)