Question

A train is approaching at platform with a speed of 20 km per hour a bird sitting on a pole at the platform When train is 2 km away from the pole brakes are applied so that the train this decelerate uniformly simultaneously the bird also flies was the rain with a velocity 60 kilometre per hour .its touches the nearest point on the train and flies back and back again and so on. the total distance travelled by the bird before train stop is:

Answer 1

${v}^{2} - {u}^{2} = 2as$
using this v =0 and u=20km/hr s=2
we get -400 = 2a(2)
a=-100
time to stop the train
v=u +at
0=20 - 100t
t=1/5hr
so bird will travel for d distance
d=vt
d=60(1/5)
d=12km

Answer 2

Answer:

using this v =0 and u=20km/hr s=2

we get -400 = 2a(2)

a=-100

time to stop the train

v=u +at

0=20 - 100t

t=1/5hr

so bird will travel for d distance

d=vt

d=60(1/5)

d=12km