Question

can someone please explain this solution to me. i have an exam tomorrow and this is from my professors's exam last year.

Answer 1

please...

Answer 2

@Mashy

Answer 3

its ok i ll try and explain here.. if you have any vector.. it can be resolved.. to find its effect in a given direction

like shown.. in this case, i have resolved vector A.. along my x axis (some random axis i was interested in) and another perpendicular to it..

this is important.. because.. most of the times.. we are only interested in the effect of a vector along our given axis.. one example.. is imagine A was a force on a block, and the block was moving along that x axis.. then for that blocks motion, the entire vector A is not important, only its effect along x axis is importnat..

similarly.. as your skater goes up that hill.. slope.. whatever.. it starts decelerating cause of gravity.. now gravity acts downwards.. but we are not interested in that entire g vecotr.. cause we only need its effect along our slope.. get it?! so we have to resolved it!