Physics 9702 · AS & A Level · Energy conservation

Energy conservation — practice question

The power $P$ needed to move an object through a medium at constant speed is determined by the speed $v$ and the resistive force $F$ acting on the object. The resistive force $F$ is also determined by the speed $v$. Which row gives a possible relationship between speed $v$, resistive force $F$ and power $P$?

  • Aresistive force $F$ proportional to $v$, power $P$ constant
  • Bresistive force $F$ proportional to $v$, power $P$ proportional to $v$
  • Cresistive force $F$ proportional to $v^2$, power $P$ proportional to $v^2$
  • Dresistive force $F$ proportional to $v^2$, power $P$ proportional to $v^3$

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