Question

Yogesh and Manav are running on a straight road. If at an instant Manav has uniform speed 28 m/s and yogesh starts from rest with acceleration of 4 m/s2 from a point 80 m ahead of manav, if both are running in same direction then find out time when yogesh overtakes manav :-​

Answer 1

Answer:

Explanation:

Option (b)

At t = 0 sec,

  speed of the man = u  

  distance of the bus ahead of the man = d

  acceleration of the bus = a

  initial speed of the bus = 0

Suppose the man meets the bus at time t sec.

Distance traveled by the man in t sec = u * t

Displacement of the bus during time t = 0 * t + 1/2 * a t²

The condition for the man to catch the bus:  

         u * t ≥ d + 1/2 * a t²

         a t² - 2 u t  +  2 d ≤ 0

The value of t is real if and only if discriminant is ≥ 0.

=>     4 u² ≥ 8 a d

=>      u² ≥ 2 a d

=>      d ≤ u² / (2 a)