Читать книгу Physics I For Dummies - Steven Holzner - Страница 50

You already have an idea of what speed is; it’s what you measure on your car’s speedometer, right? When you’re tooling along, all you have to do to see your speed is look down at the speedometer. There you have it: 75 miles per hour. Hmm, better slow it down a little — 65 miles per hour now. You’re looking at your speed at this particular moment. In other words, you see your instantaneous speed.

Instantaneous speed is an important term in understanding the physics of speed, so keep it in mind. If you’re going 65 mph right now, that’s your instantaneous speed. If you accelerate to 75 mph, that becomes your instantaneous speed. Instantaneous speed is your speed at a particular instant of time. Two seconds from now, your instantaneous speed may be totally different.