Mission KC3 Speed and Velocity
Hold down the T key for 3 seconds to activate the audio accessibility mode, at which point you can click the K key to pause and resume audio. Useful for the Check Your Understanding and See Answers.
Grandma Henderson challenges Michael Johnson in the 400-meter dash. Grandma H spins her wheelchair wheels five times and gives up 15 meters from the starting line. MJ makes a complete circle around the track and stops at the starting line. In this race, ____.
Definition of Speed:
The speed of a moving object refers to how fast the object is moving. It is the distance traveled per unit of time.
Definition of Velocity:
The velocity of a moving object is the rate at which the object changes its position.
Average speed calculations are based upon measurements of distance and time. Speed, being based upon the scalar quantity distance, is ignorant of and unaffected by changes in the direction of travel. Suppose that a person walks 12 meters, east and then 4 meters, west in 10 seconds. The distance traveled is 16 meters and the average speed is 1.6 m/s. The fact that there was a direction change is irrelevant to any measurement of the distance and speed. Speed simply keeps track of the rate at which distance is being covered. Since a change in direction does not affect the coverage of distance, it will not affect the speed.
