Cornell Notes 2.3 - Speed
October 30, 2012 - Pages 55 and 57
Objective: Students will be able to parse units of speed into their two components
The Big Idea: SPEED EQUALS DISTANCE OVER TIME!
· Speed is the most common measurement used to describe the motion of objects.
· Speed is defined as the rate of change in position.
· The faster your speed, the more your position changes over time.
· A speed of 0 means that you’re not changing position at all!
· Once you know an object’s speed, you can figure out how far it can go in a certain amount of time.
· You can also predict how long it will take to get somewhere.
· The speed of a bicycle is the distance it travels divided by the time it takes.
· Although we use many different measures for speed, the one we will use most in class is meters per second (m/s)
· 1 m/s is equal to about 2.24 mph
· The speed found by dividing the total distance by the total time is the average speed.
· Instantaneous Speed is how fast you’re going right now – what it says on your speedometer.
· Average Speed is how fast you’ve been going over time (like for an hour or two.)
· For example, when you drive, you don’t always goes exactly 55 mph. Sometimes you do 60, sometimes 50. But if you cover 55 miles in one hour, that’s an average speed of 55 mph.
· An equation can be used to calculate speed, distance, or time if two of the three values are known.
· Speed equals distance divided by time. (v=d/t) (v stands for velocity, which is just speed with a direction
· There are Three Equations having to do with speed
1. v=d/t (Speed equals distance over time)
2. d=v*t (Distance equals speed times time)
3. t=d/v (Time equals distance over speed)