According to the concept of length contraction, what happens to the length of an object as it approaches the speed of ligh and then slows down, eventually coming to a stop? o it is always observed as contracting it is always observed as the same length o it is observed as expanding and then contracting back to its original length o it is observed as contracting and then expanding back to its original length

When an object moves its length contracts in the direction of motion. The faster it moves the shorter it gets in the direction of motion. The object in this question moves and then stops moving. So it's length first contracts and then expands to its original length when the motion stops. The speed doesn't have to be anywhere near the speed of light. When the object moves its length contracts no matter how fast or slow it's moving.

Explanation:

When an object moves its length contracts in the direction of motion. The faster it moves the shorter it gets in the direction of motion. The object in this question moves and then stops moving. So it's length first contracts and then expands to its original length when the motion stops. The speed doesn't have to be anywhere near the speed of light. When the object moves its length contracts no matter how fast or slow it's moving.

i believe the answer is a hope it and is correct

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me