1. Motion, Speed, and Velocity
Physics
Motion, Speed, and Velocity

2. How is motion described?
When an object changes its position, motion has occurred.
Distance- How far an object has moved.
Point of reference- Used to show that an object is in motion. The POR is a nonmoving object

3. What is Speed? Distance an object travels per unit of time
How is speed calculated?
Speed = Distance/ Time = d/ t
Constant Speed- speed does not change over time
Average Speed- speed of motion when speed is changing
Avg Speed = Total Distance/ Total Time
Instantaneous Speed- speed at any given moment in time (speedometer)

4. Speed Problems
Calculate the speed of a swimmer who swims 100 m in 56 s
A passenger train travels from Boston to New York, a distance of 350 km, in 3.5 hours. What is the train’s speed?

5. How is velocity different than speed?
Velocity is the speed and direction of an object’s motion.
88 km / hr southwest

6. Mrs. Tabor travels 700 miles to Ohio. It takes her 12 hours
Mrs. Tabor travels 700 miles to Ohio. It takes her 12 hours. What is her speed? What is her velocity? `

7. What is on the horizontal axis? What is on the vertical axis?
Graph distance on the y-axis and time on the x-axis
Slope = rise = distance = speed
run time

8. Distance - Time Graph
If something is not moving, a horizontal line is drawn.
If something starts out slow and then speeds up, its change in speed can look like this.

9. Learning Checkpoint This graph shows several stages of motion:
Stage 1: 100 m in 10 s
Stage 2: 50 m in 10 s
Stage 3: 150 m in 20 s
Calculate the speed as indicated by each of the colors.
Calculate the average speed.
What is the total distance?

10. Solution Stage 1: S= d/ t 100 m/ 10 s= 10 m/s Stage 2: S= d/t
Ave Speed= Tot d/ Tot t
300 m/ 40 s= 7.5 m/s
Distance = 300 meters