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

admin

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 followid;pa f 72 hcxri3f/s-9jc;ptb xcno9uo+l2 *lng 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 :0o 4hdbqnbqzn8o(6bhkj q+ ) be written in terms of fundamental units by considering the equations youdz6n k(qqb:4nb8)hjoqbo+h 0 would use to calculate the derived value. By 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: $$ \mathrm{kg} \times \mathrm{ms}^{-2} \times \mathrm{ms}^{-1}=\mathrm{kg} \cdot \mathrm{m}^2 \cdot \mathrm{s}^{-3} . $$