本题目来源于试卷: Kognity IB Physics A.0 Measurements & Uncertainty，类别为 IB物理学
[单选题]
Which of the following cop 7mk +oo+ey*euld be a unit p- x0 2qf2pwibd dvz r,pn+91hof power?
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 considerinc4g s z7j)o*o01 bdjipg the equations you would use to calculate the derived value.
By replacing each term with 1j04zcp io 7g osbd)j*its unit in the equation, you can obtain 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: $$ \mathrm{kg} \times \mathrm{ms}^{-2} \times \mathrm{ms}^{-1}=\mathrm{kg} \cdot \mathrm{m}^2 \cdot \mathrm{s}^{-3} . $$
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