Originally Posted by
astronomerroyal
Regarding the pushing/pulling of things up hills. A quick scribble reveals that given an incline of A degrees, and pushing/pulling a mass M up this hill against gravity, this requires the same force as lifting (vertically) a mass Meff, given by
Meff=0.017 M A
for small (i.e all realistic) inclines A. To use the previous example, pushing the 3000 lb car up a 1 degree incline is like lifting a mass of 51lbs, which is perfectly doable. A 500lb trailer would be a mere 8.5 lb equivalent. Obviously bicycle gearing also becomes the issue.
For human propulsion, comparing the trailer mass to the human's mass (i.e. the ratio) is relevant, since humans are generally configured to be able to shift weights comparable to their body weight.
You've lost me here. The numbers aren't making sense to me. If I understand this correctly, there is no additional weight factor on a flat surface since it a zero degree incline. Multiplying by zero gives zero.
But I know from experience with loaded bikes that the weight will make a difference every time. On a flat surface, you'll be slowed down considerably the more weight you're carrying, no matter how you're hauling it. And the moment you get an incline, you're simply going to add to the effort.
If I don't understand the numbers, please explain them to me.