本题目来源于试卷: Physics Unit4: Force Dynamics & Newton's Laws，类别为 通用国际物理
[单选题]
A packing crate slides down an sgskaz+ib/7. inclzit7 1l1a78 qb6 r+0vs8 jpy3..jeqopeo icthined ramp at constant velocity. Thus we can deduce th1pqhq0j 76 zal o8. vty1o+.ee is3ptric8jb7at
A. a frictional force is acting on it.
B. a net downward force is acting on it.
C. it may be accelerating.
D. it is not acted on by appreciable gravitational force.
参考答案: A
本题详细解析:
暂无
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