A small ball is hung by a string from the ceiling of a train car, so that the ball hangs vertically. Moving from rest, the train car accelerates forward, and continues to accelerate. A team of scientists observes the behavior of the ball from various locations. From which scientist's frame of reference does the motion of the ball appear to violate Newton’s Law of Inertia? A.
on the train station platform
B.
inside of the train car
C.
in a second train car moving with constant speed in the same direction as the first train
D.
in a third train car moving with constant speed opposite the direction of the first train

Amplify and switch electrical power and electronic signals

The rocks expand when there hot/warm  and contract when they are cold.

Answertraveling around a circular trackexplanation"traveling around a circular track" is the best answer as you could be traveling around a circular track at a constant speed. your velocity would therefore have the same magnitude but will always be constantly direction. since acceleration is the rate of change of velocity, the rate of change will only involve the direction of velocity and not the magnitude.wrong choices: "an object at rest" does not accelerate at all"increasing speed while traveling around a curve" means that the acceleration will not be constant due to only change in direction; it will be constant due to both magnitude and direction"an object in free fall" does not necessarily change direction 

Answer body lying face up ;