>>4
>>5
I know how v=u+at, v^2=u^2+2as and s=ut+0.5at^2 are derived. I just don't see how energy relates to force, I understand relativism, but the fact that you need 3 times as much energy to accelerate relative to an observer from a mere 1m/s to 2m/s compared to the acceleration from 0 m/s to 1m/s doesn't make sense. Even with air resistance and friction a car expending the same amount of energy will not experience a drop in acceleration by that amount.
Let's say a space maglev of 1 kilogram which experiences no resistance converts 1 joule of electrical energy into 1 joule of kinetic energy per second.
power=1, M=1
At first it accelerates enormously since the energy needed to accelerate to get from standing to 0.01 m/s is...
E = 0.5v^2 = 0.00005
and because 1 joule of kinetic energy is provided per second it takes 0.00005 seconds to get to 0.01 m/s
This the equivalent of hitting concrete after jumping off a 30 storey building.
When it reaches 1 m/s it's mean acceleration is at the reasonable rate of 0.5 m/s.
However it will take 3 times as much energy to reach 2 m/s as I explained. This means it's acceleration has dropped by a third even though it has used the same amount of energy to propel itself throughout it's acceleration.