emm, i m new member here maybe i m stupid and young enuf to ask these question, but i seriously nid help from u all to explain to me 1st, if we standing on a weighing machine in a lift, when the lift accelerate downward, the reading of W.M. wil decrease?and when accelerate upward the reading wil increase? 2nd, according to newton third law, every action there is an opposite and equal reaction, so y thing in the world can move, said if an object of 5kg move wif acc of 2ms-2, force is 500N, then the reaction force mus be 500N isnt it?so net force eventually become 0N, so y would it move? sry these question maybe really low standard, but it seems to be hard for me, since i m still young and cant understand wat the book say, nid u all to explain thanks btw!!!