A sled of mass m is being pulled horizontally by a constant horizontal force of magnitude f. The coefficient of kinetic friction is μk. During time interval t, the sled moves a distance s, starting from rest

Yes it can cause that

Bbecause i need points 

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.