The most important thing is to try and extinguish a fire if a fire extinguisher is near. If not, they second most important thing is to rush out of the lab using the fire escape route and call the local fire department which will then handle the situation.
weight=mass*gravitational accelaration
we know the weight and the gravitational acceleration
400N=m*10m/s^2
m=400N/10m/2^2
m=40kg
Let's just say that everyvyear, many people either get the vaccination, or the flu. These people are left immune to the strain of flu that they were vaccinated/infected with so the number of people who can get and pass on that form of flu (think of these people as that flu strain's "habitat") is reduced. If some of that flu mutates sufficiently that the immune systems of those previously infected vaccinated people no longer recognize it, then it's habitat is expanded back to the original size again.
Hope this helped :)
Have a great day
