No they do not they just need to be in each other's magnetic field
<span>While you're going to the store, your acceleration changes. Some times it increases your overall speed sometimes it reduces it. Constant acceleration does not occur because it would mean that you would constantly accelerate and eventually go past the store. Even reduction of speed is a type of acceleration in physics. When you reach it, we can then calculate how much your velocity was on average and analyze how changing acceleration would've affected it.</span>
<span>c) what is the angle (relative to the horizontal) of the balls initial velocity?
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I'm pretty your it's magnetism though. Like magnets
B, since it is the only one that actually conserves matter for certain. In each of the others, matter could still be imbalanced, since for A, for example, it could be 5 Carbons on the right and 5 Chlorines on the left, and that would not balance.