Answer:
The correct option is
a. v = [tex]g (1-e^{-bt})/b[/tex]
Explanation:
Time at which the object start fall t = 0
The acceleration a is given by a = g - bV
Where V = Speed of the object
Speed V² = u² + 2·a·h
However with the drag force the object will approach terminal velocity as t becomes progressively larger whereby v will stop increasing
Option a. is the only option that has limiting value of v which is in the range of g as t increases ∴ option a. is the correct option.
v = [tex]g (1-e^{-bt})/b[/tex] as t increases [tex](1-e^{-bt})[/tex] → 1 s and v→ g/b m/s
