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.

### 2 Answers

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 schoolconservation of momentum – m1u1+m2u2= v x (m1+m2)

(90×10) +(120x-4)=v(210)

v=2m/s