Two objects of equal mass move toward each other with equal speeds. They stick together upon collision. What is their combined kinetic energy after the collision?
ATwice the KE of one object before the collision.
BEqual to the KE of one object before the collision.
CZero.
DHalf the KE of one object before.
Explanation
📌 By momentum conservation, if p_1 = +mv and p_2 = −mv, total momentum is zero. Combined object has (2m)v_f = 0, so v_f = 0. Since v = 0, KE = 0. All initial KE became heat, sound, and deformation. Distractor A/B/D: fail to recognize that combined momentum is zero here.