Scalar vs. Vector Quantities:
Scalar quantities: Have magnitude (size) but no direction. Have magnitude (size) but no direction. Examples: distance (10m) Examples: distance (10m) time (6 s) time (6 s) speed (12.3 km/h) speed (12.3 km/h) Scalar quantities are sometimes represented by letters in italic type. Scalar quantities are sometimes represented by letters in italic type.
Vector quantities: Have both magnitude (size) and direction. Have both magnitude (size) and direction. Examples: * position (12 km due south) Examples: * position (12 km due south) * displacement ( 3m upward) * displacement ( 3m upward) * velocity ( 13.5 m/s downward) * velocity ( 13.5 m/s downward) Vector quantities are usually represented in physics by using a vector arrow above the symbol, or boldfaced type. Vector quantities are usually represented in physics by using a vector arrow above the symbol, or boldfaced type.
The The need for speed… I feel the need ……
What does speed have to do with it? (km/h)
How do we calculate speed? Gilles-Villeneuve Gilles-Villeneuve Gilles-Villeneuve Site of the Canadian Grand Prix. The track is km (2.747 miles) in length. The race length is km ( miles) with 69 laps. The track record was set in 1998 by Michael Schumacher in a Ferrari F310B V10 with a time of 1m sec and a speed of km/h ( miles/h). Monza Monza Site of the Italian Grand Prix. The track is 5.77 km (3.585 miles) in length. The race length is km ( miles) with 53 laps. The track record was set in 1997 by M. Hakkinen in a McLaren MP4 / 12-Mercedes V10 with a time of 1m sec and a speed of km/h ( miles/h). The track is the fastest on the calendar; average speeds of almost 250 km/h and top speeds of almost 350 km/h are the rule. Site of the Italian Grand Prix. The track is 5.77 km (3.585 miles) in length. The race length is km ( miles) with 53 laps. The track record was set in 1997 by M. Hakkinen in a McLaren MP4 / 12-Mercedes V10 with a time of 1m sec and a speed of km/h ( miles/h). The track is the fastest on the calendar; average speeds of almost 250 km/h and top speeds of almost 350 km/h are the rule.
Speed = distance__ time Speed: describes how fast something is moving. It is a scalar quantity (does NOT indicate direction) Example 1: At Monza, top speeds of almost 350km/hr are the rule for Formula 1. Example 2: High speed elevators (like the ones in the CN Tower in Toronto), can attain a speed of 7.11m/s
Average vs. instantaneous speed… As an object moves, it often undergoes changes in speed. As an object moves, it often undergoes changes in speed. For example, during an your drive to school, there are many changes in speed. For example, during an your drive to school, there are many changes in speed. Rather than the speed-o-meter maintaining a steady reading, the needle constantly moves up and down to reflect the stopping and starting and the accelerating and decelerating. Rather than the speed-o-meter maintaining a steady reading, the needle constantly moves up and down to reflect the stopping and starting and the accelerating and decelerating. One instant, the car may be moving at 50 km/hr and another instant, it might be stopped (i.e., 0 km/hr). One instant, the car may be moving at 50 km/hr and another instant, it might be stopped (i.e., 0 km/hr). Yet during the course of the trip to school the person might average 25 km/hr. Yet during the course of the trip to school the person might average 25 km/hr.
Instantaneous Speed - speed at any given instant in time. Average Speed - average of all instantaneous speeds; found simply by a distance/time ratio. Average speed = total distance__ Average speed = total distance__ total time total time
Example: While on vacation, Karen traveled a total distance of 440 km. Her trip took 5 hours. What was her average speed? speed= d / t s = 440km / 5hr s = 88km/hr