問題詳情
38. As shown on the right, a ball of mass m is attached to a pivot fixed in place by means of a string of length L. The ball is in a state of rest. A constant force F is applied horizontally to cause the ball to swing upwards. What is the kinetic energy of the ball when the string makes an angle of θ with the vertical line?
(A) FL(1-cosθ)
(B) FLsinθ
(C) FLtanθ+ mgLsineθ
(D) FLsinθ + mgL(cosθ-1)
(E) 0
參考答案
答案：D
統計：A:0,B:0,C:0,D:0,E:0
難度：計算中