\documentclass{article}
\usepackage{exam2}
\usepackage{amssymb}
\usepackage{graphicx}
\usepackage{amsmath}
\usepackage{epstopdf}
\paper{PHYS 2210}               % <- do not include FC, FT etc

\title{Homework 5}
\time{Start of class on Thurs. Feb 10. }
\semester{Spring}
\year{2011}                     % <- default is the current year
%\campus{City}
\note{ Feb 10 is our first in-class exam day!  You may bring one side of one page of paper with your own {\it hand written} notes, if you like. Please read the LAST homework question first, so you know it's coming. This may require some planning on your part. }
\begin{document}
\begin{questions}


\question
\begin{figure}[htc]
\centering
{\includegraphics[width=2.0in]{Hom5fig1.eps}}
\end{figure}

Steve Jr. (mass $m_s$) is  standing at one edge of a 4 m long canoe (mass $M_c$) (See Fig. 1). He observes a turtle on top of a rock standing close to the other edge of the canoe. Steve wants to catch the turtle and starts walking towards it. Ignoring water friction:
\begin{enumerate}
\item Qualitatively describe  the motion of the system (canoe+ Steve) as Steve walks forward.  If initially the canoe is 3m away from the dock, where  is Steve  with respect to the dock when he reaches the other end of the canoe? (We want a formula in terms of $m_s$, $M_c$, and the given starting dimensions) 
\item If $m_s=40$ Kg and $M_c=30$ Kg and Steve can stretch his arm 1m away the  canoe edge, can he catch the turtle?
\end{enumerate}



\question A flat plate of mass M  has a triangular shape with the dimensions shown in Fig.2. The plate has a uniform density ( mass per unit area in this case).  
\begin{figure}[htc]
\centering
{\includegraphics[width=2.5in]{Hom5fig2si.eps}}
\end{figure}
\begin{enumerate}
\item Based on your physical and mathematical intuitions, without calculating, where do you predict the center of mass is, and why?
\item  Now mathematically determine its center of mass coordinates. Does your answer match your intuitions from part a? Briefly, explain (or reconcile!)
\end{enumerate}


          
 \question  Exam review!  (The rest of this homework is required, and you should turn it in. But, for obvious reasons, the grader will not look over what you write in {\it detail}, each part will be graded simply ``credit/no credit")  Our exams are designed to take one hour (though you have 75 minutes of class time to do it) It will likely be 4 questions (each multiple parts), so we figure $\sim$15 min/question.




On our website, in the syllabus, after our ``Introduction" paragraph, there is a link to our course goals. Go there, read that page. Then -
\begin{enumerate}
\item  Find in the textbook (Taylor, or one of the ``recommended" texts available in the Physics library reserve),   or invent  a plausible exam question covering material we have covered so far this term  (You might also explicitly think about what we've covered in Boas, too - can you ``hook that in"? ) Write it  down.
\item   Solve it. (Include your solution with your homework) (If it takes $<\approx$ 5 min, how could we have made it a little more interesting/richer/challenging? If it takes $>\approx$ 20 min, how could we scaffold/hint/simplify to get at the interesting physics, without making it tedious/grungy?)

\item Write a brief (just a few words) summary which characterizes what {\it content} this problem covers (e.g, ``position vectors in polar-coordinates", or ``Newton's law in tilted Cartesian coordinates", or etc)

\item Which of  the course scale learning goals does your problem address (list them by number)  (See http://www.colorado.edu/physics/phys2210/phys2210$\_$sp11/course$\_$goals.html



% \item Repeat the above, for Chapter 1 (or Chapter 3, at least what we've covered so far)  material.
\end{enumerate}




\question  Get together with at least one other person from class, and share your made-up exam question. Do theirs, and discuss with them whether you think they got the level and coverage right.
To turn in to us:
\begin{enumerate}
\item Write down the name(s) of the person you worked with
\item To show us that you really did this activity (yes, this IS a homework problem, for credit!), write down in your homework the problem of theirs that you did. (If it's really long, paraphrase)
\end{enumerate}


%{ \it Extra credit question for this week: }
%A collision  between two bodies is defined to be elastic if the total kinetic energy before and after the collision is the same. Consider an elastic collision between two identical atoms. One moves with velocity $\vec{v}_1\neq 0$. the other starts at rest $\vec{v}_2= 0$. Denoting  $\vec{v}'_{1,2}$ the corresponding velocities after the collision:
% Write down the vector equations representing  the conservation of momentum and the scalar equation representing the conservation of kinetic energy in an elastic collision. Use this to prove that the angle between  $\vec{v}'_{1}$ and  $\vec{v}'_{2}$ is $\pi/2$. Can you think of a situation where this might prove to be useful?

    %      {\it  We have not yet begun  our discussion  of energy conservation. Nevertheless  the  knowledge you have from prior years should be  enough to solve this problem.}
\end{questions}
\end{document}

