Reading about Acceleration, Newton’s Second & Third Laws

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Newton’s Second Law

Newton’s Second Law is one of the toughest of the laws to understand but it is very powerful. In its mathematical form, it is so simple, it’s elegant. Mathematically it is F=ma or Force = Mass x Acceleration. An easy way to remember that is to think of your mother trying to get you out of bed in the morning. Force equals MA! (Did I mention physics jokes are usually pretty bad?)

In English, Newton’s Second Law can be stated a few different ways: The more mass something has and/or the faster it’s accelerating, the more force it will put on whatever it hits. F=ma For example, a car colliding at 30 mph will hit a lot harder than a bumblebee colliding at 30 mph.

The more mass something has, the more force that’s needed to get it to accelerate. a=F/m This, by the way, is a mathematical definition for acceleration. For example, it is a lot harder to get a train to accelerate than it is to get a ping pong ball to accelerate.

Now here’s an interesting definition. The definition of mass can be stated as m=F/a. In other words mass is how much force it takes to accelerate something. This is a major difference between mass and weight. Something with great weight on Earth may be weightless in space (since there’s no gravity) but it will still be just as difficult to get it to accelerate.

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