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The problem would be in obtaining a coupling efficiency of 60%, i.e. making sure most of the kinetic energy was converted into gravitational potential energy in the car, rather than being wasted on stuff like work of fracture in your bones
I think it's reasonable to assume an inelastic collision, in which a crushed and broken combination of Khornight2 and bicycle temporarily sticks to the side of the car before falling away in a crumpled bloody heap. In which case, conservation of angular momentum (with the pivot point at the base of the car's tires on the far side) will give the initial angular velocity of the car's CoM, from which we can work out how much kinetic energy was delivered.
Do you still have the figures you found for the car's mass, width and CoM height ?
Nick.Earthloop-
I was wondering, if I hit backpack first would an equal amount of energy be transfered with less shoulder crumple?
@IR, I'm 6'1 and yeah the natural thing to do is try to go over things, but I recon I can get my mass down low for a hit. #poloplayer #examericanfootball
As much as tipping one on it's back looks like fun I'm less sure I could get an up and over push from my bike on the front. -
will give the initial angular velocity of the car's CoM, from which we can work out how much kinetic energy was delivered.
Not really, as you'd also want to know its moment of inertia to make that calculation.
Do you still have the figures you found for the car's mass, width and CoM height ?
My first approximation was based on 500kg and 1200mm, actual figures are more like 880kg and 1650mm, still no real idea of the height of the CoG other than speculation based on how easily they can be rolled - anything which can be rolled on a flat smooth road on street tyres must be falling over once it gets past about 45ยบ
The advantage of the energy calculation is that it's easy on both sides, and you just have to guess the hysteresis. If you try to tackle it as a momentum problem, you have to keep switching between linear and angular, and you still have to convert to energy at some point because of gravity, you're not just trying to get the car turning about its long axis, you're having to lift it too. Also, the energy calculation shows you that it's impossible before you even have to get involved in anything more complicated.
Khornight2
gbj_tester
The force isn't quite the thing you're after, although you clearly have to exceed some minimum required to lift the car. Looking at the energy, it seem that ~5kJ would be enough to raise the car by tilting until the centre of gravity fell outside the ground contact area. 100kg cyclist at 13m/s has ~8.5kJ of kinetic energy. The problem would be in obtaining a coupling efficiency of 60%, i.e. making sure most of the kinetic energy was converted into gravitational potential energy in the car, rather than being wasted on stuff like work of fracture in your bones. I'd guess, based on a first approximation, that you couldn't tip it over just by crashing into it. On the other hand, you could probably tip it onto its tailgate by lifting the front :-)