We are asked to determine the force acting upon a person given the mass and acceleration. To do that we will use Newton's second law, that is:

Where "m" is the mass and "a" is the acceleration. Replacing the given values:
![F=(50\operatorname{kg})(5(m)/(s^2))]()
Now we solve the product. We need to have into account that the product of the units is defined as N (newtons):

Therefore, the force is 250 Newtons.