Concept 1: describing motion

Sound travels at 330 m/s. If a lightning bolt strikes the ground 5 m away from you, how long will it take for the sound of the strike to reach you?

.02 seconds

A man drives south to work every day. If his 55 mile commute usually takes .75 hours, what is his average velocity?

73.33 m/hr south

The cross country team goes on a 10 mile run after school. They end the run outside of the locker room, where they started. Find the distance and displacement of the runners.

distance ~ 10 miles displacement ~ 0

A family travels 110 km east to spend the night in a hotel. The next day they drive back home, but after travelling 45 km west they decide to stop and stay with friends for the night. Find the distance and displacement of the family.

distance ~ 155 km displacement ~ 65 km east

A car drives 215 km west and then 85 km south. Find the distance and displacement of the car.

distance ~ 300 km displacement ~ 231.2

motion

change in position

instantaneous speed

the speed of an object at one instant of time

Velocity

the speed of an object in a particular direction

If you ran 3.1 miles in 0.5 hours, what is your speed?

6.2 m/hr

reference point

A place or object used for comparison to determine if an object is in motion

Displacement

Distance and direction of an object's change in position from the starting point.

Distance

How far an object moves

Speed

The distance an object travels per unit of time

average speed

The overall rate of speed at which an object moves; calculated by dividing the total distance an object travels by the total time.

Sketch the following distance over. time graph; An object moving at an constant speed

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Sketch the following distance over. time graph; An object not moving

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Sketch the following distance over. time graph; An object speeding up

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Sketch the following distance over. time graph; An object slowing down

look at the image