A football kickoff receiver catches the ball and is
about to be tackled head-on by one of two possible opponents. If the two opponents have different masses (m1 m2), but equal momentums (p1=p2),which opponent would the receiver be wise to avoid: $p_1=m_1v_1$ or $p_2=m_2v_2$? Explain why.

Question

A football kickoff receiver catches the ball and is
about to be tackled head-on by one of two possible opponents. If the two opponents have different masses (m1> m2), but equal momentums (p1=p2),which opponent would the receiver be wise to avoid: $p_1=m_1v_1$ or $p_2=m_2v_2$? Explain why.

anonymous · Answer

In both cases, his change of momentum will be p1=p2, the same.

Next, compare kinetic energy:

Starts with (1/2) m v^2, ends with (1/2)(m +m1)v'^2 or (1/2)(m+m2)v"^2,
as an inelastic collision. Figure out which give greatest energy change, presumably somewhat damaging/painfu.