Chapter 2: MOTION AND SPEED. Section 1—DESCRIBING MOTION. Motion occurs when an object changes its position. To know whether the position of something has changed, you need a reference point . A reference point helps you determine how far an object has moved. .
Section 1—DESCRIBING MOTION
An important part of describing the motion of an object is to describe how far it has moved, which is distance. The SI unit of length or distance is the meter (m).
1 meter = 100 centimeters
s = d
t 10 min
t 0.25 h
traveling at a speed of 60 km/h; located 100 km east of your location
(VELOCITY = DIFFERENT)
Section 2: ACCELERATION
However, an object that is slowing down also is accelerating (negative acceleration). In both cases, acceleration occurs, because its speed is changing.
Acceleration is the rate of change in velocity.
Section 3—MOTION AND FORCES
gravity pulling down on your body