An object of mass m=3 kg is is given an initial downward vel…

An object of mass m=3 kg is is given an initial downward velocity of 50 m/sec and then allowed to fall under the influence of gravity. Assume the gravitational force is constant g, and the force due to air resistance is proportional to the velocity of the object with proportionality constant b = 5 N-sec/m. Choose the correct set up of the initial value problem for  the velocity of the object  v(t).