Newton's 3rd Law

Philosophical or not, nearly everyone has heard of Newton's 3rd law:

 For every action (force) there is an equal and opposite reaction (force).

Yes, it can be applied to real life to reason that your little brother probably will plot revenge upon you for eating his ice cream, but it is mostly used for physics. That is, every time you push upon something with a force, that something pushes back on you with the same magnitude of force.

 For example, if Branson, the boy in the picture, pushed his seal plushie with a force of 10N, the seal, irregardless of being inanimate, pushes back on Branson with a force of 10N in the opposite direction. Thus, the force exerted both ways is the same. However, the accelerations of the seal and Branson would be different. This goes back to Newton's 2nd law, in which Fnet = m*a. Essentially, because Branson has a bigger mass than the plushie, he will accelerate slower than the plushie will. (Mass and acceleration are inversely related, remember?)