But is the ball propelled by an internal combustion engine, or is it victim of the gravitational pull?
Because if it's the former I feel it's remiss of you to forget that cold air is more compressible (or rather more easily pulled in larger quantities) than hot air, and therefore results in a more favorable stoichiometric ratio chambered and more power. Seriously, man, get your examples right! You can't omit details like that. On Thu, Feb 14, 2013 at 1:08 PM, Andy Jones <andy.jo...@gmail.com> wrote: > The example of running around on a track is wrong unless you're on a > stationary planet. Way to confuse Olivier, guys :( > > Here's my stab: Definitions aside, velocity describes how something is > moving at an instant in time. Force, however, is more closely related to > how an object will accelerate over time (in that the acceleration of the > object is directly proportional to the forces acting upon it). So if a > force is acting on an object, that will cause it to start moving > differently as time passes, like what happens when you drop something. > When you drop a ball, gravity (a force) causes its downward velocity to > increase more and more as time passes. > > A noteworthy exception to this simple explanation of forces and velocity > are forces that are actually dependent on velocity. In practice, one of > the most common such forces is the force of friction with a surface, such > as a table top (or even the surface of air against the object, which is a > component of the "drag" force affecting an object traveling through a > medium). For example, as an object travels faster and faster through the > air, the force of friction with the air will increase. This is why when > you first drop a ball it speeds up on its way down, but once it's falling > fast enough, it will stop speeding up and continue at a constant speed (and > constant velocity, if you're a stickler for terminology). Once the ball is > falling at a fixed speed, you know that the force of gravity and the force > of drag/friction are equal and opposite, such that they cancel out. > > This is of course ignoring secondary effects, such as the heat generated > by the people below arguing over email forums about how physics works. In > this case, as the arguing increases, the amount of hot air released > increases, and the air surrounding the ball becomes thinner, reducing the > drag force on the ball, and causing it to fall even faster, thereby > increasing the speed at which the ball hits its intended target, hopefully > reminding that target that it's silly to get worked up over Newtonian > physics, since it's a simplified approximation of reality anyway. > > - Andy > >
