That's a great example, now lets talk about Newton's second law. Simple enough, Newton's second law is just force = mass x acceleration
If you didn't already know, mass is the measure of how much matter you take up, and acceleration is just your change in velocity (direction and speed).
Now let me give you an example of Newton's second law. If I go out on a walk and come across a big rock and a big feather, it will take more force to move the rock. This is because the rock has more mass.
Does this mean that if I can cut down on a little bit of my mass, my reindeer will need less force to travel across the world, making it a faster, less strenuous trip?
I guess it does.
I should go on a diet!
Ok lets move on to Newton's third and final law! Every action has an equal and opposite reaction!