A tain, travelling at 20km/hr is approaching a platform. A bird is sitting on a pole on the plateform. When the train is at a distance of 2km from pole, breakes are applied which produce a uniform deceleration in it. At that instant the bird filed towards the train at 60 km/hr and after touching the nearest point on the train files back to the pole and then files towards the train and continues repeating itself. Calculate how much distance will the bird have before the train stops?

Answer

12 km

Explanation

Deaceleration of train,
`a=|(v^(2)-u^(2))/(2s)|=(20xx20)/(2xx2)=100 km//hr^(2)`
Time to reach platform `=20/100=1/5` hr
`:.` Total distance travelled by the bird`=vt=60xx1/5=12 km`