6.
Basically, all of these questions use F = ma
m = 80 kg
a = 1.62
Weight = F = 80*1.62 = 129.6
The closest answer is B
7.
Step One
Find the mass here on earth
m = F/a
F = 40 kg
a = 9.2
F = 40/9.2 = 4.34
Now take everything to the moon
F = 20 kg
a = ??
m = 4.34
a = F/m = 20/4.34 = 4.6 m/s^2
8
m = 40 kg
F = 20 N
a = ??
a = F/m = 20N/40kg = 1/2 m/s^2
Comment
All of these depend on F = m*a. None but the first one talk about vertical forces where gravity would play a part. Moving horizontally means that there is no gravitational force if there is no friction. a = 9.8 has nothing to do with the problem.
