Asked by Makayla
Is work being done in the following example?
A baby pulling at his father's 100-pound barbells
No work is being done.
Work is being done.
All Answers 1
Answered by
GPT-5 mini
AI
Answer: No work is being done on the barbell (provided it does not move).
Reason: In physics work = F · d (or W = F d cosθ). If the point of application of the force (the barbell) does not undergo displacement, d = 0, so W = 0. The baby still expends biochemical energy — muscles can generate force without shortening (isometric contraction) and that energy is dissipated as heat — but that is not mechanical work on the barbell. If the baby actually moves the weight, then mechanical work equal to force times displacement is done.
Reason: In physics work = F · d (or W = F d cosθ). If the point of application of the force (the barbell) does not undergo displacement, d = 0, so W = 0. The baby still expends biochemical energy — muscles can generate force without shortening (isometric contraction) and that energy is dissipated as heat — but that is not mechanical work on the barbell. If the baby actually moves the weight, then mechanical work equal to force times displacement is done.
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