NTA Abhyas JEE Main2020PhysicsMotion in One DimensionPractice
The motion of a body falling from rest in a resistive medium is described by the equation d v d t = a - b v , where a and b are constants. The velocity at any time t is
Options
- Aa ( 1 - b 2 t )
- Ba b ( 1 - e - b t )
- Ca b e - t
- Da b 2 ( 1 - t )
Correct answer
B. a b ( 1 - e - b t )
Step-by-step solution
d v d t = a - b v or ∫ 0 v d v a - b v = ∫ 0 t d t or - 1 b l o g a - b v 0 v = t or a - b v a = e - b t or a - b a v = e - b t v = a b ( 1 - e - b t )