Motion

Measuring Motion

Observing Motion• Motion~when an object changes position

over time when compared to a reference point

• Reference point~an object that appears to stay in place in relation to an object being observed for motion

Speed Depends on Distance and Time

• Speed~ the rate at which an object moves

• SI unit for speed~ meters per second (m/s)

• Average speed= total distance divided by total time

• Graph~ distance vs. time=speed– Straight line indicates constant speed

Velocity• Velocity~ the speed of an object in a

particular direction

• Velocity changes as speed or direction changes

• Combining velocities (Resultant velocity)– In same direction, add together

– In different direction, subtract

Resultant Velocity

Acceleration• The rate at which velocity changes

• Not just how much velocity changes, but how fast it changes

• Examples: text page 113

• Circular motion~ an object traveling in a circular motion is always changing direction

• Centripetal acceleration~ acceleration that occurs in a circular motion

Acceleration=Final velocity – starting velocity

Time it takes to change velocity

Acceleration Graph• Your Subtopics Go Here

Centripetal Acceleration• Object traveling in a circular motion is

always changing direction– Velocity always changing

– Acceleration occurs