A person travels distance x with speed v₁ and then another equal distance x with speed v₂ in the same direction. If the average velocity is v, the correct relation is:
Options

Question

A person travels distance x with speed v₁ and then another equal distance x with speed v₂ in the same direction. If the average velocity is v, the correct relation is:

G1 Physics · Accepted Answer

Total displacement: s = x + x = 2x Total time: t = x/v₁ + x/v₂ Therefore, v = 2x / [x/v₁ + x/v₂] = 2v₁v₂/(v₁ + v₂) Taking reciprocal: 2/v = 1/v₁ + 1/v₂ Hence option C follows.