A man weighs 784.8 N. What is his mass in kilograms?
1 kilogram is equal to 9.81
so 784.8/9.81 = mass in kilograms.
784.8 N = 80kg this also depends on the force of gravity.
On earth it is 80kg!
Remember F = ma (this is the equation StarStrike used)
F/a = m
784.8/9.81 = 80 kg
You should get a coversions chart they are really useful.