1. Chapter 3: Motion, Acceleration, and Forces
Table of Contents
Chapter 3: Motion, Acceleration, and Forces
Section 3.1: Describing Motion

2. Describing Motion 1
Motion and Position
(A.)Motion occurs when an object changes its position relative to a reference point.

3. Describing Motion 1
Distance
An important part of describing the motion of an object is to describe (B.) how far it has moved, which is distance.

4. Speed 1 Speed is the distance an object travels per unit of time.
Describing Motion 1
Speed
Speed is the distance an object travels per unit of time.
(C) Rate is any change over time

5. Describing Motion 1
Calculating Speed
The SI unit for distance is the meter and the SI unit of time is the second (s), so in SI, units of speed
are measured in (D) meters per second (m/s).

6. Describing Motion 1
Calculating Speed
Sometimes it is more convenient to express speed in other units, such as kilometers per hour (km/h).

7. Describing Motion 1
Changing Speed

8. Describing Motion 1
Instantaneous Speed

9. Calculating Velocity
Formula (E)
V=d/t
d– distance
t– time

10. Describing Motion 1
Graphing Motion
The (F) motion of an object over a period of time can be shown on a distance-time graph.
(F1.) Time is plotted along the horizontal (x) axis of the graph and the (F2.) distance traveled is plotted along the vertical (y) axis of the graph.

11. Acceleration, Speed and Velocity2
Acceleration, Speed and Velocity
(A.) Acceleration occurs when an object changes its speed, its direction, or both.

12. Calculating Acceleration2
Calculating Acceleration

13. Calculating Positive Acceleration2
Calculating Positive Acceleration
(B1.) The slope of the line represents the acceleration.
(B2) x-axis is time
(B3.) y-axis is speed

14. Speeding Up and Slowing Down
Acceleration 2
Speeding Up and Slowing Down
If the (C) acceleration is in the same direction as the velocity,
the speed increases and the acceleration is positive.

15. Speeding Up and Slowing Down
Acceleration 2
Speeding Up and Slowing Down
If the (D) speed decreases, the acceleration is in the opposite
direction from the velocity, and the acceleration is negative.

16. Calculating Negative Acceleration2
Calculating Negative Acceleration

17. Motion and Forces 3
What is force?
Sometimes it is obvious that a force has been applied.
But other forces aren’t as noticeable.
(A.) Unit of force is the Newton (N)

18. Motion and Forces 3
Balanced Forces

19. Motion and Forces 3
Unbalanced Forces

20. Air resistance
(B1.) Causes objects to fall with different accelerations and different speeds.
(B2.) Air resistance acts in the opposite direction of the velocity.
(B3.)Amount of air resistance depends on the speed, size, and shape of the object falling.

21. Terminal Velocity
(C1.) Terminal velocity is the highest velocity a falling object reaches.