Everything Science Grade 10

21.6 CHAPTER 21. MOTION IN ONE DIMENSION

DEFINITION: Instantaneous speed

Instantaneous speed is the magnitude of instantaneous velocity.

Quantity: Instantaneous speed (v) Unit name: metre per second

Unit symbol: m·s−^1

Instantaneous velocity is a vector. Instantaneous speed is the magnitude of instantaneous

velocity. It has the same value but is not a vector so it has no direction.

Description of motion ESAHA

The purpose of this chapter is to describe motion, and now that we understand the defi-

nitions of displacement, distance, velocity, speed and acceleration, we are ready to start

using these ideas to describe how an object or person is moving. We will look at three

ways of describing motion:

1. words

2. diagrams

3. graphs

These methods will be described in this section.

We will consider three types of motion: when the object is not moving (stationary object),

when the object is moving at a constant velocity (uniform motion) and when the object is

moving at a constant acceleration (motion at constant acceleration).

Stationary Object ESAHB

The simplest motion that we can come across is that of a stationary object. A stationary

object does not move and so its position does not change.

406 Physics: Mechanics