1. The problem statement, all variables and given/known data An arctic hunter goes hunting polar bears and shoots one. He finds it lying dead on a large patch of almost frictionless ice. He has no scales or weighing device of any kind (and of course, there's nothing to hang it on) but he does have a long rope. How can he get a pretty good estimate of the weight of the bear? Give a detailed answer, perhaps with a sample calculation. Reasonable assumptions may be made. Answer does not have to be a specific number, but may be a re-arranged formula for the unknown with all other variables being easily substituted for by the hunter. 2. Relevant equations While force equations may be used (F=ma), this question is meant to be answered using equations involving momentum and velocity. total initial momentum= total final momentum therefore, m1v1i + m2v2i = m1v1f + m2v2f, where m1= mass of hunter, v1i=initial velocity of hunter, m2= mass of polar bear (unknown), v2i=initial velocity of polar bear, and v(1 or 2)f = final velocity of hunter or polar bear respectively. Ek=1/2mv^2 Ep=mgh Et = (Ekf-Eki) + (Epf-Epi) Other possible equations: Ep=-GMm/r 3. The attempt at a solution Honestly, I have absolutely no idea where to start. I have attempted to use the momentum formula above, making the assumptions that the hunter knows his own mass, as well as that he can judge his own velocity and that of the polar bears (if he runs or drags the polar bear). If i set vi for both the polar bear and hunter to 0, my masses would also be zero, so instead, I attempted the problem by making v1i=2m/s and v2i=2m/s also because if the hunter tied one end of the rope to the polar bear and ran with it, pulling with even tension, the polar bears speed would also equal the hunters. when substituting a random number for the hunter's mass, and 5m/s for the v1 and v2 f I kept ending up with m2=-8 ( negative the hunter's mass). Then, calculating weight, W=mg, =(-8)(-9.8) i get 78.4kg - a reasonable weight for a polar bear - but how can m1=m2??? the masses of a polar bear and hunter i'm assuming will be very different - so they cannot have the same mass or the same weight. I have no idea where to go from here and I've been working on this application question for a couple days now - any ideas or changes in scenario? (a.k.a other things the hunter may do with the rope?) I thought of a different scenario - one where the hunter could tie the ends of the rope to himself and the polar bear, and then going and standing right next to it. If he starting running till the point where he reached the end of the rope and the rope was taught - would the hunter's kinetic energy at that point = polar bear's potential energy? Even so, how does h from (Ep=mgh) factor in, if the polar bear is being held at no height? Please help! This is due Monday and I'm nowhere near being able to understand how to solve this! I did try asking my teacher but she refused to give any hints or answer any clarification questions, saying to just read the question over.