Topic 2: Mechanics
Created 13 April 2026 21:18
Tags Notes
Motion
Speed, Distance & Time
Key definitions
Speed - The rate at which an object covers distance, without
considering its direction.
Displacement - The overall change in position of an object in a specific
direction.
Velocity - Speed with direction, or how quickly displacement changes
over time.
Acceleration - How quickly velocity changes over time, indicating a
speed increase or decrease in a particular direction.
Scalar and Vector Quantities
Velocity and acceleration are vector quantities, meaning they include both
magnitude (how much) and direction (which way). The average speed of an
object during a trip is the total distance travelled divided by the total time
it took. The instantaneous speed is the speed of an object at any specific
moment.
Topic 2: Mechanics 1
, Introducing SUVAT
In SUVAT problems, each letter represents a quantity:
s - displacement (m)
u - initial velocity ( m s1)
v - final velocity ( m s1)
a - acceleration ( m s2)
t - time (s)
SUVAT equations
Motion can be represented through a variety of motion equations:
v = u + at
1
s = ut + at2
2
v 2 = u2 + 2as
(u + v)t
s=
2
Motion Graphs
Displacement-time graphs
Displacement-time graphs show how far an object has moved from its
starting point (displacement) and the time it took to move that distance.
Topic 2: Mechanics 2
, Key features include:
Y-axis represents displacement: The vertical axis shows the distance
from the start point, in meters.
X-axis represents time: The horizontal axis indicates the time, usually
in seconds.
Shape of the graph: A straight horizontal line indicates no movement,
a straight sloping line indicates constant speed, and a curve shows
changing speed (acceleration or deceleration).
When an object accelerates, its speed changes over time. Acceleration
appears as a curved line on a displacement-time graph.
If the acceleration is constant, meaning it doesn't change, the curve on the
graph will be smooth and regular. This shows that the speed of the object
is increasing at a steady rate.
The gradient of a displacement-time graph is velocity
Velocity can be calculated by dividing the change in displacement by the
change in time. On a graph, this calculation is represented by the gradient,
which is calculated as:
Δy change in displacement
gradient = =
Δx
change in time
For graphs that show acceleration, this gradient is not constant; it changes
along the curve.
Velocity-time graphs
Topic 2: Mechanics 3
Created 13 April 2026 21:18
Tags Notes
Motion
Speed, Distance & Time
Key definitions
Speed - The rate at which an object covers distance, without
considering its direction.
Displacement - The overall change in position of an object in a specific
direction.
Velocity - Speed with direction, or how quickly displacement changes
over time.
Acceleration - How quickly velocity changes over time, indicating a
speed increase or decrease in a particular direction.
Scalar and Vector Quantities
Velocity and acceleration are vector quantities, meaning they include both
magnitude (how much) and direction (which way). The average speed of an
object during a trip is the total distance travelled divided by the total time
it took. The instantaneous speed is the speed of an object at any specific
moment.
Topic 2: Mechanics 1
, Introducing SUVAT
In SUVAT problems, each letter represents a quantity:
s - displacement (m)
u - initial velocity ( m s1)
v - final velocity ( m s1)
a - acceleration ( m s2)
t - time (s)
SUVAT equations
Motion can be represented through a variety of motion equations:
v = u + at
1
s = ut + at2
2
v 2 = u2 + 2as
(u + v)t
s=
2
Motion Graphs
Displacement-time graphs
Displacement-time graphs show how far an object has moved from its
starting point (displacement) and the time it took to move that distance.
Topic 2: Mechanics 2
, Key features include:
Y-axis represents displacement: The vertical axis shows the distance
from the start point, in meters.
X-axis represents time: The horizontal axis indicates the time, usually
in seconds.
Shape of the graph: A straight horizontal line indicates no movement,
a straight sloping line indicates constant speed, and a curve shows
changing speed (acceleration or deceleration).
When an object accelerates, its speed changes over time. Acceleration
appears as a curved line on a displacement-time graph.
If the acceleration is constant, meaning it doesn't change, the curve on the
graph will be smooth and regular. This shows that the speed of the object
is increasing at a steady rate.
The gradient of a displacement-time graph is velocity
Velocity can be calculated by dividing the change in displacement by the
change in time. On a graph, this calculation is represented by the gradient,
which is calculated as:
Δy change in displacement
gradient = =
Δx
change in time
For graphs that show acceleration, this gradient is not constant; it changes
along the curve.
Velocity-time graphs
Topic 2: Mechanics 3
