a 2 kg object is moving horizontally with a uniform velocity of 4 m/s.how much net force is required to keep the object moving at this speed and in this direction
NO net force is required to keep a moving object moving in a straight line at a constant speed. In fact, if you apply ANY force to it, in ANY direction, then its speed, its direction, or both must change, and its velocity won't be uniform any more.
I know we never see this in our daily life. Whenever we see an object moving, it always stops. That's because the net force on it is never zero ... there's always some gravity or some friction acting on it. That's what you have to put up with when you live on Earth.