Question

Can someone help with these?

Answer 1

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.