Chapter 6, Problem 31P

a man of mass m₁ = 70.0 kg is skating at v₁ = 8.00 m/s behind his wife of mass m₂ = 50.0 kg, who is skating at v₂ = 4.00 m/s. Instead of passing her, he inadvertently collides with her. He grabs her around the waist, and they maintain their balance. (a) Sketch the problem with before-and-after diagrams, representing the skaters as blocks. (b) Is the collision best described as elastic, inelastic, or perfectly inelastic? Why? (c) Write the general equation for conservation of momentum in terms of m₁, v₁, m₂, v₂, and final velocity v_f. (d) Solve the momentum equation for v_f. (e) Substitute values, obtaining the numerical value for v_f, their speed after the collision.