If the mass of a body is 5kg, its weight on the surface of the earth would be
Weight on the surface of the earth is the measure of the force acting on the body because of acceleration due to gravity.
If we have a body of mass 5 kg and the acceleration due to gravity as 9.8m/s2
weight = mass x acceleration due to gravity
weight = 5 x 9.8 = 49 N