Recent content by nalA

pervect, I meant the shortest path including time ...

Thanks! Yes you were right, I was imagining the "hovering" path - it does start to make more sense now! and I should have remembered that s=ut+0.5at^2 oops! I started reading the spacetime entry on wikipedia which helps too. I didn't really appreciate how much "longer" a second was compared...

Been reading laymen's books on general relativity and I'm in need some clarification! ... Line 1: The shortest path from a point 9.8 meters above the surface of the Earth to another point at the same location in space but 1 second later in time. Line 2: The shortest path from a point 9.8...

That makes things a lot clearer, thank you for your patience!

Thanks! All those links look great! I'll have good read of them. Bear with me here! Is this a bit like using a 2 dimensional constant circular motion to explain the 1 dimensional movement of an oscillating weight on a spring? What I mean is: There is nothing physically moving in a 2...

I feel like I'm still missing something. I think you're right - perhaps it's the diagrams that are confusing me because they all seem to be showing spacetime (represented by a 2 dimensional surface) being curved through a higher dimension to produce the geometrical effects mentioned above ...

The youtube video posted above was great for visualizing why the apple falls from the tree's point of view - thanks! In fact all those links to visualizations were really helpful. Got some questions ... When spacetime is 'bent' by mass is it being bent through a higher dimension than the 3+1...

I'm interested in the theoretical minimum number, so like the extruded buckyball ball? I'm trying to work out if there are enough carbon atoms in a 'piece of paper' to reach the moon. :) Which brings me to the next question : how many carbon atoms are there in a piece of paper? Or...

This is a bit of a silly question, but one I'm curious about ... It all started when I made a status update on facebook proclaiming that if you could fold a piece of A4 paper in half 44 times it would reach the moon. One of the commenters made an interesting point by saying: I...

I understand your point and yes it does add more complications. However, I like it because it means the white ball can be an ordinary snooker ball and doesn't need to be made of a mysterious super dense material. The Earth has such an enormous mass compared to that of a red snooker ball that...

edit: no problem. yes - they do appear to prove me right now :) edit: well actually - I've realized a mistake I made in my original argument with my colleagues - I didn't think that an inelastic collision would affect the speed of the red ball either, but I can see that it obviously does now -...

Could this same problem be viewed from the frame of reference of the white ball? For example - a white ball of normal mass is fixed securely to the top of a short pole that is fixed securely to the ground. The red ball is dropped from a short distance above the white ball, such that it hits...

Thanks for that :) Yes - you can assume they're not spinning - imagine a collision in free space, it could be assumed to be a one dimensional problem. One of the things we're arguing about is the speed of the white ball afterwards (for all types of collision: perfectly elastic, perfectly...

Ah yes, that does help. So would it be correct to say that the velocity of the red ball after the collision would be ... MW.VWB + MR.VRB + MW.CoR.(VWB - VRB) ------------------------------------------- MW + MR where CoR = Coefficient of Restitution But since MW >> MR and VRB = 0...

You've given me the two extremes - which I agree with by the way - but I'm interested in the middle ground - not perfectly elastic, or inelastic. And simplifying: If MW >> MR then 2MWVWB/(MW+MR) \approx 2VWB for perfectly elastic and MWVWB/(MR+MW) \approx VWB for perfectly...