Weight of the body on Earth = 98 N.
Acceleration due to gravity on Earth = 9.8 m/s2.
Let 'm' be the mass of the body on Earth.
m = W/g
m = (98/9.8) = 10 kg
Thus, the mass of the body is 10 kg, which always remains constant.
(a) Mass on moon = mass on Earth = 10 kg
(b) Let weight on moon is W'.
W' = mass × acceleration due to gravity on the Moon.
[Given, acceleration due to gravity on the Moon = 1.6 m/s2]
W' = 10 × 1.6 =16 N.