Over the break I went sledding and there was a lot of physics involved. Firstly, I climbed to the of the hill and put my sled on the ground, it did not move, illustrating Newton's 1st law that an object at rest will stay at rest. In order to make my sled go, my friend has to push on me. The push demonstrates Newton's 3rd law, that for every action there is an equal and opposite reaction.
When my friend pushed on me she exerted the exact same force on herself. Additionally, the sled was able to remail on the hill thanks to gravity pushing it down, but there is also the normal force on me which keep the forces balanced. As I went down the hill I moved with increased momentum because the hill acted similarly to a box on a ramp. The higher the incline, the faster the speed.