Question 3
A man has a mass of 60 kg. What is his weight? (Take g = 10 m s−2.)
The right answer is the one marked above.
600 N. Weight is the product of mass and the acceleration due to gravity:
weight = m g = 60 kg × 10 m s−2 = 600 N
This is the equation F = ma itself — the only difference is that the acceleration substituted in is the acceleration due to gravity.
60 N comes from forgetting to multiply by g. Note that the answer must always be in newtons.