An 89.5 kg fullback moving east with a speed of 5.7 m/s is tackled by a 81.5 kg opponent running west at 2.58 m/s, and the collision is perfectly inelastic.

(a) Calculate the velocity of the players just after the tackle.
m/s
(b) Calculate the decrease in kinetic energy during the collision.
J

2 answers

LOL, they clung to each other after so after the crash the total mass is
89.5 + 81.5 = 171 kg

now east, the fullback I call +x

initial momentum
= 89.5*5.7 - 81.5*2.58
= 431 kg m/s

final momentum
= 171*v
Newton #1 say those are identical so
171 v = 431
v = 2.52 m/s
initial ke = (1/2)89.5(5.7)^2 + (1/2)81.5(2.58)^2

final ke = (1/2) 171 (v)^2