A train of 150 m length moves towards east at a speed of 10 m/s. A bird flies at a speed of 5 m/s towards west
parallel to the railway track. The time taken by the bird
to cross the train is equal to​

when insulating materials rub against each other, they may become electrically charged . electrons , which are negatively charged, may be 'rubbed off' one material and on to the other. the material that gains electrons becomes negatively charged. the material that loses electrons is left with a positive charge.

answer a fan shaped mass of sediment deposited at the base of a mountain front do to an abrupt change in stream gradient;