Ravneet
Last Activity: 6 Years ago
NOTE at the different instant train’s all parts( head or tail )move with constant acceleration ‘a’ or in other words with same speed
when the head of train crosses pole, the speed of train be u
let, train’s length is d
so after travelling d distance, the tail of train crosses pole and speed of train be v
Applying kinematics equation, v2 = u2 + 2ad,
calculate ‘a’ from here
Now when middle portion crosses pole, the speed of train be z and distance travelled by train will be d/2
applying kinematics equation , z2 = u2 + 2a(d/2) put a here
calculate z
that will be the answer
ANS { ( v2 + u2 ) / 2 }1/2
