JEE Main2003PhysicsMotion in One DimensionActual
A body travels a distance s in t seconds. It starts from rest and ends at rest. In the first part of the journey, it moves with constant acceleration f and in the second part with constant retardation r . The value of t is given by
Options
- A2 s ( 1 f + 1 r )
- B2 s ( 1 f + 1 r )
- C2 ~s 1 f + 1 r
- D2 s(f+r)
Correct answer
A. 2 s ( 1 f + 1 r )
Step-by-step solution
Portion OA, OB corresponds to motion with acceleration ' f ' and retardation ' r ' respectively. Area of O A B=S and O B=t . Let O L=t₁ , LB = t ₂ and AL = v , S = 1 2 OB AL = 1 2 t v ; v = 2 ~S t Also, f = v t ₁ , t ₁= v f = 2 ~s tf and r = v t ₂ , t ₂= v r = 2 ~s tr ; t = t ₁+ t ₂= 2 ~s tf + 2 ~s tr t= ( 1 f + 1 r ) 2 s t t= 2 s ( 1 f + 1 r )