What is the weight of a ball with a mass of 77 kilogram?

Answer 1

Short answer

1.3 x 102 N (on moon)

7.5 x 102 N (on Earth if g = 9.80 N/kg

Long Answer

Since the category is "The Moon" gravity will be assumed to be 1.63 m/s2 (N/kg = m/s2)

http://en.wikipedia.org/wiki/Gravitation_of_the_Moon

W = mg

W = (77 kg)(1.63 N/kg) = 125.51 -> 1.3 x 102 N (significant figures)

for earth, just substitute in 9.80 N/kg for 1.63 N/kg

W = (77 kg)(9.80 N/kg) = 7.5 x 102 N