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 followi kxowm,xy kdm28hyy4 f-(,di;xjl* q. v:/z3 dfe6 4sql nx,bang could be a unit of 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 o 1l p*-*h.r tukd:l 0-kv/ kic.pu8l2 vzlpsskf fundamental units by considering the equations you would use to calculate the derived value.
By .k20lu*sv:l dptkui8 cz1llpv*.--k shkp/r replacing each term with 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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