Answer:
An object which moves in the positive direction has a positive velocity. If the object is slowing down then its acceleration vector is directed in the opposite direction as its motion (in this case, a negative acceleration).
Explanation:
Your list of choices is a very short list, and doesn't include any
correct explanation.
The mass of an atom is roughly the number of protons AND neutrons
in its nucleus, but the element only depends on how many protons are there.
Different atoms of the same element may have different numbers of
neutrons, so their masses are different. But they're the same element,
because they all have the same number of protons.
Answer:
1992 (Early 1990s)
Explanation:
First of all, i would like to define an extrasolar planet as a planet that orbits a start that is not our own.
The first confirmed detections of extrasolar planets occured in the early 1990s (specifically 1992, some say 1995). The name of the first extrasolar planet is widely believed to be called Dimidium or 51 Pegasi b.
Extrasolar were searched by monitoring stars for slight dimming that might occur as unseen planets pass in front of them.
Energy flows with kinetic energy
