In this chapter, we will learn about force and motion, beginning with how objects can be at rest and in motion simultaneously, illustrated with examples. Additionally, we will identify different types of motion, including translatory (linear, random, and circular), rotatory, and vibratory motions, and distinguish among them. We will also differentiate between distance and displacement, as well as speed and velocity, providing relevant examples for clarity. Furthermore, we will explore scalar and vector quantities, representing vector quantities through drawing. Moreover, we will define key terms such as speed, velocity, and acceleration, and learn how to plot and interpret distance-time and speed-time graphs. Finally, we will determine and interpret the slope of these graphs to ascertain the state of a body, whether it is at rest, moving with constant speed, or moving with variable speed.

TYPES OF MOTION

If we observe carefully, we will find that everything in the universe is in motion, though different objects exhibit various types of movement. Some move along a straight line, while others travel in a curved path or follow different patterns altogether. There are three primary types of motion: translatory motion, which can be further classified into linear, random, and circular motions; rotatory motion; and vibratory motion, characterized by a to-and-fro movement.

In physics, we encounter various quantities, such as mass, length, volume, density, speed, and force, which we categorize into two types: scalars and vectors.

Scalars are physical quantities that can be fully described by their magnitude alone, which refers to their numerical value along with the appropriate unit, such as 2.5 kg, 40 s, or 1.8 m. Common examples of scalar quantities include mass, length, time, speed, volume, work, and energy.

SCALARS AND VECTORS

Vectors, on the other hand, are defined by both magnitude and direction. Examples of vector quantities include velocity, displacement, force, momentum, and torque. Without direction, a vector would be incomplete; for instance, knowing the distance of a location from a reference point is not enough to identify it. The direction from that reference point is also essential for proper location. Thus, a vector quantity is fully described by its magnitude and direction.

Acceleration

When does a body experience acceleration? In many situations, a body’s velocity changes due to alterations in its magnitude, direction, or both. This change in velocity leads to acceleration. Acceleration is defined as the rate at which the velocity of a body changes.

A body exhibits uniform acceleration when it experiences equal changes in velocity over equal time intervals, no matter how short those intervals may be.