if a ball is thrown westwards at 140 kmph from a train moving eastwards at 80 kmph, what will be the speedof the ball?
taking east as +ve
velocity of train (say u )= 80 i
and velocity of ball be v
the velocity of ball given is wrt train..
then velocity of ball = -140 i wrt train.
velocity of ball wrt train = v - u
-140 = v - 80
v = -60 i
thrfr the velocity of ball wrt ground = 60 km/hr westward..