a roller coaster car may be approximated by a block of mass m. the car, which starts from rest, is released at a height h above the ground and slides along a frictionless track. the car encounters a loop of radius r, as shown. assume that the initial height h is great enough so that the car never loses contact with the track.

Which of the following is an example of an opposing signal? no examplthates given.   i would say, that traffic lights in a city at major intersections direct the flow of traffic in opposite directions so would be an example.also, stop signs on either side of the same street would be an example. at a train crossing, the light for allowing car traffic in opposite directions or not would be another example.

May strike workers if the load swings, twists, or turns.