Yes, that's why it slows down and starts to fall. If there were no gravity, when you threw the rock up, it would keep travelling at a constant velocity.If I were to throw a rock up in the air, is it always accelerating at 10 m/s22 even up until it stops and starts falling back down?
Wouldn't it, for example be, a=-Constant/r^2, where r is the distance to the focus where the Big Chunk is in place?This thread made me think of another question. I'm going to post it here because it's closely related, but feel free to move it elsewhere.
In the simplest possible terms (no math, please), how would one describe the acceleration of a satellite in an elliptical orbit? My instinct is that it's constantly changing, but I'm not sure.
I agree with this opinion, velocity and acceleration is a vector quantity that has direction. so the value of the velocity and acceleration, can be positive and negative depending on the direction.The following statements apply to one-dimensional motion (so that a sign is sufficient to indicate the direction of a vector).
The acceleration is positive when the object is moving in the positive direction and speeding up, or when moving in the negative direction and slowing down.
The acceleration is negative when the object is moving in the positive direction and slowing down, or when moving in the negative direction and speeding up.
Once again the answer is tied to the concept that acceleration is a vector concept possessing both magnitude AND direction. So even if the magnitude is constant, if the direction changes, as it does in circular or elliptical motion the acceleration always changes (provided that no other forces act on the object aside from the original one.)Wouldn't it, for example be, a=-Constant/r^2, where r is the distance to the focus where the Big Chunk is in place?