Question

acceleration is taken as negative while anything comes down..!!

and wen sumthng is thrown up its taken as positive..!!

then why in certain cases the reverse happens..?

pls explain.. wen to take + and - considering an example of a free fall..???

pls b quick.. hv xam tmr..!!

Answer 1

Giving sign to any vector (as acceleration is a vector quantity) is fully upto you...

The main thing to know about this is, you have suppose for an axis(x-y)

The vectors pointing towards the positive directions of the axes should be regarded as +ve

See the reference...