How much would a 15.0 kg object weigh on Neptune?

Weight = (mass) · (gravity)

Weight = (15.0 kg) · (11.2 m/s²)

Weight = (15.0 · 11.2) · (kg · m/s²)

Weight = 168 Newtons

The gravity on Neptune is 11.15 m/s²

the gravity on earth is 9.81 m/s²

divide the Neptune and earth gravity we get 1.13

which means object on neptune is 1.13 heavier than earth

yield, weigh of the object on neptune is 1.13*15=17.04kg