Overweight and underweight (id: f1b4926d5)

本题目来源于试卷: Overweight and underweight，类别为 美国物理杯赛(Physics Bowl)

[单选题]
15.24: A mass on a frictionless inclinznu 4vs qi403 ub26wxd l:6qaneh /fkg:ws2i ;nof1 /vt has a gravitational force,a normal force from the incline, and a force applied by a person that all are equal in magnitude. The mass remains at rest and the incline makes an angle θ counterclockwise from the horizontal. Which one of the:k/fi /stowfvg ;n1h2 following choices best describes the orientation of the applied force by the person? The +x-axis is directed upward, parallel to the incline’s surface as shown in the figure.

A. The applied force is oriented directly along the +x axis.
B. The applied force is oriented at an angle θ clockwise from the +xaxis.
C. The applied force is oriented at an angle$90^{\circ}$− θ clockwise from the +xaxis.
D. The applied force is oriented at an angle$90^{\circ}$−θ counterclockwise from the +xaxis.
E. This is a completely impossible situation that never can be realized physically.


参考答案:  C


本题详细解析: 暂无

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