Finding v(t) and x(t) for motion with quadratic drag force

[joemama69]

Homework Statement

an object moves to the right with a constant speed v, the ovbject then enters a region where the resistive force is -bv², find v(t) & x(t)

Homework Equations

The Attempt at a Solution

F_x = ma = -bv²

v = (ma/-b)^.5

how do i get t in there

 

[CompuChip]

You are treating "a" and "v" as independent now.
However, the acceleration is related to the velocity as a = dv/dt.
So your equation is actually:
m dv/dt = - b v²

You are going to have to solve a differential equation.