If jim exerts a force of 2.0 N on a shopping cart, what force does the shopping cart exert on jim?

There are two possibilities for this question:

1 - The shopping cart is at rest (not moving):

In this case:

∑Forces = 0

Force exerted by Jim + Force exerted by cart = 0

2 + Force exerted by cart = 0

Force exerted by cart = - 2

2 - The cart is moving as a result of a net force "m":

In this case:

∑Forces = m

Force exerted by Jim + Force exerted by cart = m

Force exerted by cart = m-2