Basics

What to expect

This section is the place to start if you are commencing your course or kicking your revision into gear. Having a good understanding of the basics is essential for the topics.

After studying this topic, you should be able to:

Use mathematical techniques, such as number, equations, substitution, radians and trigonometry, to solve physical problems.
Use both the Greek and English alphabets to choose the correct symbol for physical quantities.
Use units and prefixes to present the magnitude of a physical quantity.
Present data effectively using a range of techniques like linear and non-linear graphs.
Express the uncertainty in a calculated value.
Distinguish scalar and vector quantities.
Understand the concepts of density and intensity, which feature often (but do not have a natural home) in IB Physics.

Key questions

What exactly are radians?

The radian is a unit of angle, similar to degrees. When converting between degrees and radians, we use the fact that a complete circle is 360° = 2π radians. Find out more.

Is trigonometry SOH CAH TOA?

Trigonometry is the calculation of angles and lengths of triangles using maths. The sides of a right angled triangle are always in the same ratio for a given angle. These ratios are called sine cosine and tangent (sin, cos and tan). To define which side is which they are given names. Find out more.

What are the metric prefixes?

Unit prefixes are used to reduce the characters needed to represent a number. Unit prefixes are written immediately in front of the unit (without a space). Apart from the kilo (k), an uppercase prefix represents a large number and lowercase prefixes represent small numbers. Find out more.

How do you calculate percentage uncertainty?

A fractional uncertainty (or percentage uncertainty, if x100%) is the ratio of the absolute uncertainty to the measurement itself. Find out more.

What are the differences between scalar and vector quantities?

A scalar quantity is a measurement with magnitude (and usually a unit). A vector quantity is a measurement with magntiude, direction (and usually a unit). Vectors are usually drawn with an arrow in the correct direction, where the length of arrow represents the magnitude. Find out more.

How do you calculate density?

Density is defined as the ratio of the mass of a body to its volume. Find out more.

What is intensity of light in physics?

The intensity of a wave is the power incident on a surface per unit area. Find out more.

Mathematics
In physics, maths is used as a tool to solve problems related to the relationships between quantities.
Greek alphabet
Almost all of the letters of the Greek alphabet are used to represent physical quantities and units.
Units
In IB Physics there are six fundamental units from which all others required can be derived.
Prefixes
You actually get a list of these in the databook but it's better if you know them.
Presenting data
There are a few rules to follow when presenting data...
Error and uncertainty
An error is the difference between the value you determine and the true value.
Scalars and vectors
All physical quantities can be classified as either a scalar or a vector.
Density
Density is perhaps the most-used concept in physics that doesn't have a specific location in the Subject Guide. It can be used in gases, standing waves, gravitation, fuels and heat transfer.
Intensity
Density is perhaps the most-used concept in physics that doesn't have a specific location in the Subject Guide. It can be used in gases, standing waves, gravitation, fuels and heat transfer.