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SPEED
In our mind right now, the idea for SPEED might just be "fast" and "slow". We use descriptions like "this train is slower then that train, therefore, this train take us from here to there slower". It is used those words to compare speed, but not precise enough. We need to define speed carefully.
Imagine, a man driving a car steadily. When he passed a traffic light. We start timing it, and record the progress each second. It is shown on the picture above. The driver is going at a steady speed. We define speed as the distance traveled each second, or a given time unit, such as millisecond. The driver is going 10 meters per second.
WORK WITH SPEED Trying to find the speed might not be as hard as you think. It's fairly simple,
you will only need two numbers. The time that it was taken, and the distance it has traveled. After you've got those two number, calculating speed is a cinch. You can then just do distance divided by time, then you'll get the speed.
Average speed. It's like the average of your grade. You might have an A and a C, but your average is a B. Science works a lot like mathematics, you add all the numbers together, then divide by how many numbers you've added. For example, if a car is traveling 50 miles per hour, but was slowed down to 10 miles per hour while crossing the school zone. They're average speed is 30 miles per hour. (50 + 10 = 60, 60/2 = 30)
In this case, the car is not going at a steady speed. The speed changes continually, therefore, AVERAGE SPEED is being used.
We can still use the formula of speed = distance / time. but this time it tells us how fast the car is going in a overall manner. OTHER UNITS Talking about speed in meters per second makes sense for scientists. It might not be meaningful for car drivers. In some places, such as America, distances are measured in miles. We also use larger time interval hours instead of seconds. We now have car speed in miles per hour. In other countries, distances are measured in kilometers, and speed in kilometers per hour. |
[Introduction] [Straight-Line Motion] [Speed] [Velocity] [Acceleration] [Circular Motion]
[Satellites] [Force] [Gravitation] [Inertia] [Newton's Law] [Momentum] [Mass and Weight]
| PZone has | hits since August 1, 1997. |
