F.1 Speed and Acceleration

UNIT SYLLABUS

Exploring the basic principles of motion, defining speed, velocity, and how objects accelerate.

1 Key Formulas

Average Speed

v = \frac{d}{t}

Acceleration

a = \frac{v - u}{t}

2 Exam Preparation & Topic Explanations

Interpreting Motion Graphs (Criteria A & C)

Graph interpretation is one of the most common MYP exam tasks. You will be asked to describe the motion, calculate speeds/accelerations, or draw a graph from a description.

Distance–time graphs:

- Gradient = speed.

- Straight sloping line = constant speed.

- Horizontal line = stationary.

- Curved line = changing speed (acceleration or deceleration).

Velocity–time graphs:

- Gradient = acceleration.

- Area under graph = distance travelled.

- Horizontal line = constant velocity.

- Straight sloping line = constant acceleration.

MYP command terms:

- *State*: Give a specific name or value without explanation.

- *Describe*: Give a detailed account (e.g., “the object moves at constant speed then stops”).

- *Calculate*: Show working and units.

- *Explain*: Give a scientific reason.

Pro Exam Strategy

Always check the axes labels – distance or velocity – before you start.
When calculating acceleration from a v–t graph, use a large triangle to minimize error.
Past papers often give a graph and ask ‘Calculate the distance travelled in the first 10 seconds’ – find the area under the graph.
If asked to sketch a graph, label the axes with units and use a ruler for straight lines.

Common Past Paper Pitfalls

Many students lose marks by confusing speed and velocity. Speed is a scalar (magnitude only), velocity is a vector (magnitude and direction). If the question asks for velocity, you must include a direction or risk losing the mark.

Pro Exam Strategy

When converting units, remember: 1 m/s = 3.6 km/h.
In multi‑step calculations, write the formula first, then substitute numbers, then calculate – MYP rewards clear working.
If a graph shows a return to the starting point, the final displacement is zero – this often appears in ‘explain’ questions.

3 MCQ Practice

Q1. A bicycle travels 100 meters in 20 seconds. What is its average speed?

$2\, m/s$
$5\, m/s$
$20\, m/s$
$2000\, m/s$

Q2. If a car starts from rest and reaches a velocity of 20 m/s in 4 seconds, what is its acceleration?

$2\, m/s^2$
$5\, m/s^2$
$10\, m/s^2$
$80\, m/s^2$