1. Motion Notes
Ms. Rudisill

2. Motion An object is in motion if it is changing position.
Depends on two “points of reference” – a starting position and an ending position.

3. Distance
The movement of an object from one point of reference to another.

4. Displacement
The distance between the starting and ending points and the direction you have traveled.

5. Speed
Distance
Speed =
Time

6. Practice Problem #1 Distance Distance = 100 m Speed = Time
Calculate the speed of a swimmer who swims 100 meters in 56 seconds.
Distance
Distance = 100 m
Speed =
Time
Time = 56 sec
100 meters
Speed =
= 1.79 m/sec
56 seconds

7. Practice Problem #2 Distance Distance = 350 km Speed = Time
A passenger train travels from Boston to New York, a distance of 350 km, in 3.5 hours. What is the train’s speed?
Distance
Distance = 350 km
Speed =
Time
Time = 3.5 hours
350 km
Speed =
= 100 km/hrs
3.5 hours

8. Velocity
The speed of an object AND the direction of its motion.

9. Practice Problem #3 Distance Distance = 5 m (to the left) Velocity =
Calculate the average velocity of a dancer who moves 5 m toward the left of the stage over the course of 15 sec.
Distance
Distance = 5 m (to the left)
Velocity =
Time
Time = 15 sec
5 m
= m/sec to the left
Velocity =
15 sec

10. Acceleration
Change in velocity divided by the amount of time it takes for the change to occur.

11. Acceleration Equation
(Final Speed) - (Starting Speed)
Acceleration =
Time

12. Three Kinds of Acceleration:
Speeding up
Slowing down
Changing direction

13. (Final Speed) - (Starting Speed)
Practice Problem #4:
Calculate the acceleration of a bus whose speed changes from 6 m/sec to 12 m/sec over a period of 3 sec.
(Final Speed) - (Starting Speed)
Acceleration =
Time
Final Speed = 12 m/sec.
Starting Speed = 6 m/sec.
Time = 3 sec.

14. Practice Problem #4: (12 m/s) - (6 m/s) Acceleration = 3 s
Acceleration = 2 m/s2

15. (Final Speed) - (Starting Speed)
Practice Problem #5:
Calculate the acceleration of a train whose speed increases from 7 m/s to 17 m/s in 120 s.
(Final Speed) - (Starting Speed)
Acceleration =
Time
Final Speed = 17 m/s
Starting Speed = 7 m/s
Time = 120 s

16. Practice Problem #5: (17 m/s) – (7 m/s) Acceleration = 120 s
Acceleration = m/s2