Which one of the following systems would constitute an inertial reference frame?

Question

Quizplus · Accepted Answer

An inertial reference frame is a frame of reference in which Newton's first law of motion holds true. According to this law, an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force. In choice A, the weather balloon is descending at a constant velocity, which means it is moving in a straight line with a constant speed. Since there are no external forces acting on the balloon, it can be considered an inertial reference frame. The other choices involve either non-uniform motion (rocket undergoing uniform acceleration and roller coaster traveling around a corkscrew turn at constant speed) or non-zero net forces acting on the objects (orbiting space station and rotating merry-go-round), making them non-inertial reference frames.

Which One of the Following Systems Would Constitute an Inertial