Question

a body of mass 2kg is sliding with a constant velocity 4m\s on a friction less horizontal table the force required to keep the body moving with the same velocity

Answer 1

Since body is moving with constant velocity, so acceleration of the body is zero. Hence no force is acting on the body and in the absence of external force body will keep on moving with same speed according to law of inertia so no force is required to keep the body in uniform motion.