Recent content by zumulko

Thank you all for help.

K^2, thank you. Although I still can't see the magnetic lift I don't want to torture you anymore with my questions. Last thing, could you give me some reference so that I can read about details of the effect?

K^2, let me analyze it by assuming the straight line current flow due to the arc. The current produces loops of magnetic field which lie in the plane perpendicular to the direction of current. The magnetic field vectors are tangent to the loops, never at right angle to the direction of...

Thank you for your quick replies. K^2, how does exactly the magnetic field causes the upward motion? Is it about the interaction of circular magnetic field created by and around arc with the Earth magnetic field?

Can anyone please explain or suggest why the arc from video (link below) rises up? http://blog.makezine.com/archive/2010/12/now_thats_a_switch.html zumulko.

The two events are the firings. Since they are simultaneous in SS frame, dt=0. We also know that in SS frame their spatial separation is dx=5m.

To americanforest: I forgot to add that it should be solved with high school physics tools, therefore we mustn't use the invariant. To vela: I agree. We should thus divide the 6.25m by gamma factor, right?

Homework Statement A spaceship (SH) moves with speed v=0.6c relative to a space station (SS) (sic!). Two lasers, A and B, on the SS are 5.00m apart as measured by the SS observers. The gamma factor for a speed v=0.6c is 1.25. The lasers are fired simultaneously acc. to the SS observers...

Couple of days ago I hit the tree with my bike and became wiser ;) If you pull the lower string with a jerk, you give the block relatively large acceleration directed downwards, so large inertia force due to the mass of the block is directed upwards. So the upper string feels just the weight of...

I'm not quite sure about the case of pulling the lower string with a jerk, but I think the force exceeding lower string's strength is less than the weight of the heavy block. Because of the inertia of the block the force applied to the block by the lower string is still not enough to move it, so...

Let's assume that the bee is moving upward at some angle alpha to the vertical. Flaping is pushing the air particles in the opposite direction of bee movement, giving them momentum p. Then the air particles momentum p_y perpendicular to the bottom of the jar is p*cos(alpha), which is less then...

Some of the kinetic energy of the air particles moved by bee wing is transferred into the heat and radiated from the jar. Lost energy means lost momentum and hence less net force acting on the bottom of the jar. Am I wrong?