Space Time & Motion A.3 Work Energy and Power (id: f34b72e14)

本题目来源于试卷: Space Time & Motion A.3 Work Energy and Power，类别为 IB物理学

[单选题]
An electric motor is used to raise a block of mass 18.0 kg vertically to the top of a building at a constant speed of $1.5\;m\;s^{-1}$. If the power rating of the motor is 297 W, calculate the efficiency of the motor.

A. 9%
B. 75%
C. 61%
D. 91%


参考答案:  D


本题详细解析:

微信扫一扫，分享更方便