1. Calculating Speed
10-1

2. Equation for Average Speed
Speed = Distance/ Time
V= d / t

3. Velocity is speed and direction
Sometimes knowing speed is not enough, you need to know which direction an object is moving
Velocity is speed and direction

4. Speed vs. Velocity Identify the following as speed or velocity 10 m/s
15 km/hour west
435 meters/second toward the shore
2.8 km/hour

5. Math Skills Sample Problem pg 323
Metal stakes are sometimes placed in glaciers to help measure a glacier’s movement. For several days in 1936, Alaska’s Black Rapids glacier surged as swiftly as 89 meters per day down the valley. Find the glaciers velocity in meters per second.

6. Step 1 List the given and unknown values Given: time (t) = 1 day
Displacement (d) = 89 m down the valley
Unknown:
Velocity (v)= ? m / s and direction

7. Step 2 Perform any necessary conversions
* Time is given in days and it needs to be in seconds

8. Cross out units to make sure you end up in the desired unit
Time is 86,400 seconds

9. Step 3 Write the equation for speed (velocity)
Speed = displacement / time
= d / t

10. Step 4 Insert the known values and solve v = d / t
= 89 m / 8.64 x 104 s
= 1.0 x 10-3 m / s down the valley