Recent content by marcnn

Yes, the light didn't have to travel the distance, indeed. but why do we take it in account then instead of ignoring?

Whooops! I forgot to mention it. The lens is planoconvex of radius ##R##

Homework Statement There are three subquestions in this question, all marked bold. Let's consider a gradient index lens of thickness ##d##, whose refractive index changes with the distance from the axis with the following formula $$ n(r) = n_1 + a r^2 $$. Determine the lens's focal length...

Yep, I made a typo :) ##I'## is calculated to wrt to the axis which goes through the point of tangency to the wall and is parallel to the floor, I guess. The official solution of the corresponding problem isn't clear either :)

(Based on a problem from the 59th Polish Olympiad in Physics, 2009) Let's consider a ball of mass ##m##, radius ##r## and moment of inertia ##I = 2/5mr^2## approaching a wall with linear velocity ##v_0##, rolling without sliding with angular velocity ##\omega_0##. It collides with a wall. Its...

It's the original problem: http://www.kgof.edu.pl/archiwum/56/of56-2-1-R.pdf Is it what you meant? Yes, it was given in the opening post and is ##\frac {y_A}{x_A} = p##

Homework Statement (56th Polish Olympiad in Physics, II stage) A photographer has a camera with a lens of focal ##f## with can be set to a value from the interval ##[f_{min}, f_{max}]##. The diameter of the diaphragm is ##d##. The photographer wants to make a photo of a friend so that the...

Well, I've finally got it. It's so easy that I don't know how I could've missed it :P It's correct, isn't it?

Of course, I made a sign mistake, it should be $$ a_y = \varepsilon\left(\frac b2 \cos \alpha- \frac a2 \sin \alpha \right) $$

Thanks!

Homework Statement (56th Polish Olympiad in Physics, 2007) We have a tube of mass ##M##, consisting of two segments of diameters ##d_1, d_2##. The pistons (see the picture http://www.kgof.edu.pl/archiwum/56/of56-2-1-R.pdf) have mass ##m_1, m_2##. At the start the air inside had pressure...

You can see the picture here: http://www.kgof.edu.pl/archiwum/58/of58-2-1-R.pdf

Homework Statement Let's suppose we have a [cuboid](http://en.wikipedia.org/wiki/Cuboid) of dimensions ##a \times b \times c##. We put it on an inclined plane of an angle ##\alpha## so that only one edge of length ##c ## touches the plane. In time ##t = 0 ## the cuboid doesn't rotate. Let the...