phys (1124) - G forces

first day with robson as a tacher today. he's alright. he explained the g force things well at least, and a few other things.

g force is a ratio of normal weight against reaction weight. the reaction being an acceleration.

to calculate vertical g-force, we go

(9.8 + a) / 9.8

the 9.8 coming from the earth's gravity.

now since gravity has no effect on us in a horizontal direciotn, when calculating horizontal g-force, its just a/9.8.

the thing about standing on the ground, is that we have a reaction force lifting us off the ground. that would be equal to gravity (9.8). so, our weight would be 1x normal, we experience 1g. apparently normal people can experience more than 3g (evident on rollercoasters and such). they target rockets and shuttles to only have around 3g for safety of astronauts and equipment.

if we fell off a plane though, there's no floor pushing us off, we fall to gravity, thats called freefall.

the thing about g-forces, is that they're independent of peoples mass. its the same ratio, but used on different people.

eg.

a 50kg guy, and a 100kg guy experience 2g.

the first guy experiences 100kg as his weight, and the other guy, 200kg.

the amount increases depding on how much the person weighs to begin with

i asked mr robson what would happen if two planets were really close to each other. he said that there would be a point in between where we would just be stationary in the middle, otherwise it'd be up to the stronger planet.

he explained what spaghettification is. he said that in a black hole, if we fell feet first, our feet would be closer to the black hole than our head, so our feet would be pulled faster, making it stretch. catch it?