An object moves with speed v₁, v₂ and v₃ along line segments AB, BC and CD respectively as shown in figure. If AB = BC and AD = 3AB, then average speed of the object will be: Image
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An object moves with speed v₁, v₂ and v₃ along line segments AB, BC and CD respectively as shown in figure. If AB = BC and AD = 3AB, then average speed of the object will be: Image

G1 Physics · Accepted Answer

Let AB = BC = x. Since AD = 3AB, CD = x. Total distance = 3x. Total time = x/v₁ + x/v₂ + x/v₃. Therefore average speed = 3/[1/v₁ + 1/v₂ + 1/v₃] = 3v₁v₂v₃/(v₁v₂ + v₂v₃ + v₃v₁).