A 100 m long train is travelling from North to South at a speed of 30ms^(-1). A bird is flying from South to North at a speed of 10ms^(-1). How long will the bird take to cross the train?

A 100 m long train is travelling from North to South at a speed of 30m

1.	A 100 m long train is travelling from North to South at a speed of 30ms^(-1). A bird is flying from South to North at a speed of 10ms^(-1). How long will the bird take to cross the train?
Answer» 3s 2.5s 10s 5s Solution :Length of TRAIN = 100 m BIRD and train are moving in a opposite direction `:.` Relative velocity `=30+10=40ms^(-1)` Time taken to cross the train (t) `=("distance")/("R.velocity")=(100)/(40)=2.5s`.