Question

A 110 kg quarterback is running the ball downfield at 4.5 m/s in the positive direction when he is tackled head-on by a 150 kg linebacker moving at -3.8 m/s. Assume the collision is completely inelastic. What is the velocity of the players just after the tackle?

Answer 1

`v_f=-0.29(m)/(s)`

Step-by-step explanation:

The principle of conservation of momentum, states that if the sum of the forces acting on a system is null, the initial total momentum of the system before a collision equals the final total momentum of the system after the collision. The collision is completely inelastic, which means that the players remain stick to each other after the collision:

`p_i=p_f\\m_1v_1+m_2v_2=(m_1+m_2)v_f\\v_f=(m_1v_1+m_2v_2)/((m_1+m_2))\\\\v_f=((110kg)4.5(m)/(s)+150kg(-3.8(m)/(s)))/((110kg+150kg))\\v_f=-0.29(m)/(s)`