Two equal masses moving along a straight line at velocities +3 m s⁻¹ and -5 m s⁻¹ collide elastically. What are their velocities afterwards, respectively?
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Two equal masses moving along a straight line at velocities +3 m s⁻¹ and -5 m s⁻¹ collide elastically. What are their velocities afterwards, respectively?

G1 Physics · Accepted Answer

Step 1 — Principle: For a one-dimensional elastic collision, conserve momentum and kinetic energy. Step 2 — Working: For a 1D elastic collision between equal masses, the two bodies exchange their velocities: v₁′=-5 m/s and v₂′=+3 m/s. Correct answer: D — -5 and +3 m s⁻¹.