Does the earth accelerate

Answer 1

Yes, as strange as it sounds the earth is accelerating in the direction of the sun.

However when we say that, we are not suggesting that it is speeding up in the direction of the sun but merely that its velocity is changing in the direction of the sun.

It is important to understand that a velocity not only has a magnitude but it also has a direction. In general, if the magnitude and/or direction of an object's velocity is changing, we say that it is accelerating.

This means that if something is traveling and only the direction that it is traveling changes, we still say it is accelerating because the direction of its velocity is changing.

This is the case when something is traveling in a circle at constant speed. If you where to represent its velocity by a vector you would find that while the magnitude of the vector does not change over time, the direction of the vector does. In fact, over a very short period of time, if you where to represent the change in direction of its velocity by a vector, you would find that that "difference vector" points directly toward the center of the circle.

Again, this is all a bit confusing because when we generally use the word "accelerate" we mean that something is speeding up. However one just has to get use to the idea that when something is accelerating, it may be that only the direction of its velocity is changing and not necessarily its magnitude.

Answer 2

-- The Earth traverses a closed, curved path around the sun.

-- Therefore, it doesn't move at constant speed in a straight line.

-- Therefore its motion is accelerated.

The force responsible for the acceleration is the centripetal gravitational force.

Answer 3

A satellite that is circling the Earth is only accelerating only when it is losing its orbit. Otherwise, it will continue at its current speed or decelerate.

Answer 4

if your considering that there is no air resistance then acceleration stays the same or constant (Newtons Laws of Motion).