A 0.650 kg projectile is launched from the edge of a cliff with an initial kinetic energy of 1950 J and at its highest point is 131.8 m above the launch point.

(a) What is the horizontal component of its velocity?

(b) What was the vertical component of its velocity just after launch?

(c) At one instant during its flight the vertical component of its velocity is 25.41 m/s. At that time, how far is it above or below the launch point?

In each of the parts of this question, a nucleus undergoes a nuclear decay. Determine the resulting nucleus in each case.

Part A

227/89 Ac undergoes alpha decay. Determine the resulting nucleus.

For example, if the resulting nucleus is 40/20 Ca enter ^40_20Ca.

Part B

211/83 Bi undergoes beta-minus decay. Determine the resulting nucleus.

For example, if the resulting nucleus is 40/20 Ca enter ^40_20Ca.

Part C

22/11 Na undergoes beta-plus decay. Determine the resulting nucleus.

For example, if the resulting nucleus is 40/20 Ca enter ^40_20Ca.

Part D

98/43 Tc undergoes gamma decay. Determine the resulting nucleus.

Enter your answer in the space below. For example, if the resulting nucleus is 40/20 Ca enter ^40_20Ca.

1. A 58 g steel ball is released from rest and falls vertically onto a steel plate. The ball strikes the plate and is in contact with it for 0.5 ms. The ball rebounds elastically, and returns to its original height. The time interval for a round trip is 7 s. In this situation, the average force exerted on the ball during contact with the plate is closest to:

Start with a railroad car on a frictionless track and use the example of a pulse of light with energy ?E traveling from one end of the car to the other to derive ?E = ?mc 2 . You must define all terms carefully and explain each step.

consider a cube of sides l0 traveling parallel to one side. At what speed would the density of the cube double?

I've heard Astronomers talking about backlit CCD sensors, and talking about how much better they are than other types. What are they, why might I want to get one, and what are the pros/cons of this compared to related technologies?

I've heard reference to many telescope and spacecraft that have a device known as a spectrometer, and I'm curious, what is the purpose of these device? What's the working principal behind them and what do we use them for?

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!