90 likes | 224 Views
Measuring Motion. January 15, 2013. Motion. Motion is an object’s change in position relative to a reference point. Reference Points. The object that appear to stay in place is a reference point . One can also describe an object’s motion with a reference direction .
E N D
Measuring Motion January 15, 2013
Motion • Motion is an object’s change in position relative to a reference point.
Reference Points • The object that appear to stay in place is a reference point. • One can also describe an object’s motion with a reference direction. • Ex: Airplanes, Hot-air balloons.
Speed • Speed is the distance traveled by an object divided by the time taken to travel. • Airplane seen in 10 s intervals • A 500 m distance for each interval • (500 m) / (10 s), or 50 m/s • SI unit for speed: Meter per second (m/s)
Determining Average Speed • Used because objects most of the time do not travel at a constant speed. Average Speed = total distance total time
Practice Problems • What is your average speed if you take 0.5 h to walk 4,000 m? • What are you solving for? • Next, look at the values and units. • (4,000) (.5) = 8,000 m/h
Recognizing Speed on a Graph A constant straight line means the object moves at constant speed. The steeper the graph, the faster the motion. A horizontal line means the object is not changing it’s position. (It’s Not Moving!) A line curving upwards shows an increase in speed; getting steeper means it is accelerating.