Weight, in physics elaborately is a type of force which pertains to the gravitational attraction of the earth and the mass of the object.
Hence, the formula for weight is mass x gravity.
Mathematically - w = m x g
Solution:
Mass = 8 kg
Gravity = 10 m/s2
Weight = 10 x 8
Weight = 80 kg*m/s2 or 80N
Therefore the weight of the 8 kg object is 80 newton.