A string is attached to the rear-view mirror of a car. A ball is hanging at the other end of the string. The car is driving around in a circle, at a constant speed. Which of the following lists gives all of the forces directly acting on the ball?
ATension
BTension and gravity正確答案
CTension, gravity, and the centripetal force
DTension, gravity, the centripetal force, and friction
答案與詳解
