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 vz366s 4p2/ gku;g )80dhv erc kgkimja unit orzc.z3 roxb+(g ,2n+h d)*j zxy4mymg f 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 writte(-z*bwh0pbr5 -mqslbw2u l 2yn in terms of fundamental units by considering the equations you would use to calculate the derived value.
By replacing each term with its unit in the equation, you c5wbmy-w 2bsql(z*u2p -b0 h rlan 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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