Linear Motion What means of

motion has done more to change the way cities are built than any other?

                                                   

                    

ELEVATORS!!

Neglecting Air Resistance What if Aristotle

neglected air resistance?

Exposes simple relationships

Paper, books, feather & coin demos

Motion is Relative Everything Moves! Even

objects that appear at rest.

Move with respect to or relative to a reference point.

Book, Space shuttle When we discuss speeds:

Relative to Earth

Speed Speed = change in

distance/change in time

S=d/t Per = divided by Rate—divided by

time Primarily use m/s

Speed If you ride a bike a

distance of 5m in 1 sec, what is your speed? For 10m in 2 sec? For 100 m in 20 sec?

5m/s for all of these

Instantaneous Speed A car does not always

move at the same speed.

Speedometer reads the speed at a specific instant or point in time. This is known as instantaneous speed.

Student demo-walk

Average Speed Planning a trip

How long? How far?

Car certainly does not go the same speed.

You only really care what the average speed will be

Avg Speed = total distance/time interval

Average Speed If an indy car travels

a distance of 180 miles in 1.5 hrs, what is the car’s avg speed?

120 mph

Average Speed The speedometer in every car also has an

odometer that records the distance traveled. If the odometer reads zero at the beginning of a

trip and 35km a half hour later, what is the average speed?

70 km/h Would it be possible to attain this average speed

and never exceed a reading of 70 km/hr on the speedometer?

No, If the trip starts and ends from rest the highest speed must be over the avg.

Average Speed If a cheetah can

maintain a constant speed of 25 m/s, it will cover 25 meters every second. At this rate, how far will it travel in 10 seconds? In 1 minute?

250 m, 1500m