Determining initial acceleration of a projectile
How can I proceed to solve the problem below?
The problem:
A projectile enters a resisting medium at x = 0 with an initial velocity Vo = 900 ft/s and travels 4in. before coming to rest. Assuming that the velocity of the projectile was defined by the relation V = Vo - kx, where V is expressed in ft/s and x in feet, determine the initial acceleration of the projectile.