Question

What approximate "weight" is an astronaut on the moon if his mass is 80 kg? A. 128 N B. 176 N C. 784 N D. 50 N

Answer 1

weight = mass x acceleration due to gravity

= 80 kg x 1.6252 m/s^2 = 130 N (approximately).

The correct answer is A. 128 N

Answer 2

Your answer would be approximately 128 N. Here is how!
Acceleration on the Earth is 9.8m/sec^2... on the moon, it's 1/6 that, or about 1.6m/sec^2. 

So, 80kg X 1.6m/sec^2 = 128N