Sir Issac Newton was a very successful man. He created three laws that we use today. We are experiencing the first law.
Faster! Faster!
Son this is the fastest I can go.
The first law states that, if a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force.
Well why can't we go any faster?
I keep petaling but I am not able to go any faster than I was going because gravity and friction are the outside forces acting on me which is causing me to slow down and I have to pedal more and harder.