Recent content by chrisyuen

Thank you very much!

Homework Statement I read an e-book about the classical mechanics and didn't know how to find the lower and upper limits for a volume integral. Homework Equations Perhaps, it may be related to the use of similar triangle. The Attempt at a Solution I calculated the x value...

Homework Statement Homework Equations Nil The Attempt at a Solution Why does the bar y have a factor of 0.5 for the formula of area centroid? Thank you very much!

I tried some methods and found the followings finally: tan \theta = 3u = 3u / 1 Put the above result to a right-angled triangle with adjacent side = 1 and opposite side = 3u, we can get cos \theta = (9u2 + 1)-0.5. I guessed that the "a" is actually a "9" which is a typo instead. Am I...

Homework Statement Homework Equations F = uR The Attempt at a Solution I don't understand the followings: For equilibrium at A, the equation should be F1 = T sin \theta. Am I right? While for the one at B, the equation should be F2 = T sin \theta. Am I right? In...

Is it good to study Physics (Bachelor Degree) in Russian Universities? Which university is the best in Physics in Russia? How can I determine which branch of Physics should I study? Is it a must to learn Russian in order to attend the lecture? Is there any class that will use English...

Homework Statement What are the differences between Kinematics and Dynamics? Homework Equations N/A The Attempt at a Solution Kinematics does not care about the cause leading to this motion while Dynamics does, is that true?

Homework Statement What is moment of inertia? Homework Equations N/A The Attempt at a Solution Some people said that it is not a scalar and also not a vector. But other said that if it is not a vector, it must be a scalar. However, another said that it is actually a tensor...

Homework Statement (Answers: (a) 0.3233 (b) 2 (c)(i) 0.6489 (c)(ii) 0.1669 (c)(iii) 0.2369) Homework Equations Formulae for Discrete Probability Distributions The Attempt at a Solution I don't know how to solve part (b) only. For (b), I have no idea. Is it using...

Homework Statement At a school sports day, the timekeeping group for running events consists of 1 chief judge, 1 referee and 10 timekeepers. The chief judge and the referee are chosen from 5 teachers while the 10 timekeepers are selected from 16 students. (a) How many different...

I got it! Thank you very much!

Thanks for your helps!

Homework Statement Box A contains three white balls and one red ball while box B contains four white balls. One ball is randomly drawn from each box and the two balls are then randomly put back into the boxes so that each box still contains four balls. This process is performed n times. Let...

P(NS|M) = P(M|NS) P(NS) / P(M) P(M) = P(M|NS) P(NS) / P(NS|M) = P(M|NS) P(NS) / (1 - P(S|M)) = 7/8 x 4/5 / (1 - 1/6) = 21/25 P(NS|F) = P(F|NS) P(NS) / P(F) = P(F|NS) P(NS) / (1 - P(M)) = 1/8 x 4/5 / (1 - 21/25) = 5/8 Am I right?

P(S|M) = P(S and M) / P(M) = P(M|S)P(S) / P(M)? Did my tree diagram correct? Thank you very much!