Physics The Physics of Motion p. 296-297
What is Motion? What is the fastest moving object that you know of? How fast does it move? How do bats, dolphins, and auto focus cameras track moving objects? What are the smallest/largest moving objects that you know of? How would you describe their motion?
Distance The race covered a distance of 5.62km Distance measures the total length of a journey along every twist and turn of the path. Use the symbol “d” (di : initial distance, df : final distance and d change in distance df-di). Measured in metres (m) Scalar quantity-has size or magnitude but no direction
Time About 30 min. in to the movie (time), Max went out of the theatre for about 5 min. (time interval) Time describes when an event occurs. Use the symbol “t” (ti-initial time, tf-final time, and t (tf-ti) Measured in seconds (s). Scalar quantity
Position The collision occurred 24.75m due south of the flagpole. Use the symbol “d”, di (initial position), df (final position) Measured in metres (m) Describes an object’s location from a certain viewpoint. Position is a vector quantity, you need to state both magnitude and direction. The arrow represents “vector”
Displacement We pushed the car, producing a displacement of 4.5 m at an angle of 25° to the road. Displacement describes how much an object’s position has changed. Symbol: d Calculation: d = df – di Unit: m with a direction
Velocity The aircraft was travelling at 535 km/h, headed N45°W, when the weather warning was received. Velocity describes the speed and direction of motion. v : velocity vav: average velocity vinst: instantaneous velocity Unit: m with a direction
Speed Earth's average speed of revolution about the sun is 29 800 m/s! Speed describes how fast something is moving. Symbol: v Unit: m/s
Acceleration Earth’s gravity makes objects accelerate at 9.8m/s2 downward. Acceleration describes how much an object’s velocity changes in a certain time. a: acceleration aav: average acceleration ainst: instantaneous acceleration Unit: m/s2 with a direction