Kognity IB Physics A.0 Measurements & Uncertainty (id: 4a1233956)

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本题目来源于试卷: Kognity IB Physics A.0 Measurements & Uncertainty，类别为 IBDP Physics

[单选题]
Which of the following could be a unit of powerib au /mw,d:rde+ s1h1e)d0fj eunv,*(pg1 p0 xp 0btii+ 7fus?

A. $kg \cdot m \cdot s^{-2}$
B. $kg \cdot m^2 \cdot s^{-1}$
C. $kg \cdot m^2 \cdot s^{-2}$
D. $kg \cdot m^2 \cdot s^{-3}$


参考答案:  D


本题详细解析:
All derived units can be written in terms of fundamental units by cog76dfd7 6zhz tnsidering the equations you would use to calculate the derived value. By replacing each term with its unit in the equation, you can ohdt6f z7gdz76 btain the new unit. For example: $$ P=F v $$ where $P$ is power, $F$ is force and $v$ is velocity. In turn: $$ F=m a $$ where $m$ is mass and $a$ is acceleration. So we could write: $$ P=m a \times v $$ and the unit of power in terms of fundamental units must then be: $$ \mathrm{kg} \times \mathrm{ms}^{-2} \times \mathrm{ms}^{-1}=\mathrm{kg} \cdot \mathrm{m}^2 \cdot \mathrm{s}^{-3} . $$