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

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

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.

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

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).

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

Describing Motion 1 Changing Speed

Describing Motion 1 Instantaneous Speed

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

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.

Acceleration, Speed and Velocity 2 Acceleration, Speed and Velocity (A.) Acceleration occurs when an object changes its speed, its direction, or both.

Calculating Acceleration 2 Calculating Acceleration

Calculating Positive Acceleration 2 Calculating Positive Acceleration (B1.) The slope of the line represents the acceleration. (B2) x-axis is time (B3.) y-axis is speed

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.

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.

Calculating Negative Acceleration 2 Calculating Negative Acceleration

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)

Motion and Forces 3 Balanced Forces

Motion and Forces 3 Unbalanced Forces

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.

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