Question

An object is represented by the dot on the motion map.

An illustration of a circle with a black dot at the top of the circle with a vector point toward the center of the circle.
Which object is most likely represented by the dot?

a car driving over the top of a hill
a ball on a string that stopped at the top of a vertical loop
a roller coaster car at the top of a vertical loop of track
a bug on the top of a rolling hula hoop

Answer 1

A roller coaster car at the top of a vertical loop of track.

Reason: the arrow toward the circle's center indicates centripetal acceleration (a = v^2/r), which is present for an object moving in a circular loop. A ball "stopped" at the top would have v = 0 so no centripetal acceleration; the roller coaster in a loop is the clear circular-motion case.