Space Time & Motion A.2 Forces & Momentum (id: 94acb9092)

本题目来源于试卷: Space Time & Motion A.2 Forces & Momentum，类别为 IB物理学

[单选题]
A roller coaster loofxd*yb 8 1p i6vhe-kf+p has a radb yf a49roqxm1k2xfob ;fks(/ b bx33;ius R as shown in the diagram. The combined mass of a car and the passengerom(oa3f3b 1sfbbf42y ;qk;xb x9x kr /s is M


When the car goes around the top of the loop, the normal reaction force of the track on the car is equal to half of the weight of the car and passengers.
Which expression gives the kinetic energy at the top of the loop?

A. 0
B. $\frac{RMg}{4}$
C. $\frac{3RMg}{4}$
D. RMg


参考答案:  C


本题详细解析:
At the top of the loop, t k 8o-4s-b1m3evqa eavhe centripetal force is the vector sum of the combined weight of the car and the passengers, and tk3ave1vo 4q-bm- s8e ahe normal force of the track on the car.

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