A 90 kg halfback running north with a speed of 10 m/s is tackled by a 120 kg opponent running south at 4 m/s. Compute the velocity of the two players just after the tackle.
Assume that at tackle time they Stick TOGETHER (don’t bounce apart) then northern
(call it negative -) momentum is
90 x 10= -900 kg.m/sec and momentum south is 120 x 4 = +480 kg.m/sec.
now momentum is additive and conserved so the combined mass of the two players is
(-900 +480)kg. m/sec =-420 kg m.sec.so the combined bodies will move in negative direction (which is NORTH at 420/210 =2m/second.Source(s): went to school
conservation of momentum – m1u1+m2u2= v x (m1+m2)