Originally Posted by sch
Murray: just because the speed going up hill is constant does not mean the acceleration is zero.
From
http://www.m-w.com/cgi-bin/dictionar...a=acceleration
Main Entry:
ac•cel•er•a•tion
Pronunciation: ik-"se-l&-'rA-sh&n, (")ak-
Function: noun
1 : the act or process of accelerating : the state of being accelerated
2 : the rate of change of velocity with respect to time; broadly : change of velocity
What component of velocity (speed or direction) is changing when you go uphill at a constant speed?!?
Originally Posted by sch
Consider going down hill, if the hill continues the speed will gradually increase until air resistance overcomes acceleration and speed levels out.
Yes, if you drop an object, it’s speed increases (accelerates) until it reaches terminal velocity. At that point, it is no longer accelerating since its velocity is constant.
Originally Posted by sch
The inverse is also true, going up hill you must accelerate to overcome gravitational pull. If the acceleration is zero you are going to stop and fall over or roll backwards.
This would be negative acceleration. If your acceleration is zero, your velocity (speed) won’t change.
Originally Posted by sch
If your acceleration exceeds a certain level you will increase your speed up the hill, if your acceleration equals the component of gravity in the direction you are moving then you will maintain whatever speed you have. Steve
If you are maintaining your speed, you are merely counteracting one force (due to gravity) with another (pedaling force).
Back to the original point, if your speed is constant, your wheels are rotating at a constant RPM. Neglecting air and bearing resistance, it takes no additional effort to maintain the rotation of the wheels regardless of how much the wheels weigh. In fact, the heavier wheel will maintain its rotation longer when subjected to similar bearing loads and air resistance. But, as F!_Fan stated, I’ll take the lighter wheels every time!
-murray