Calculating Speed 10-1

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

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

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

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.

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

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

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

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

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