amber
general physics
1.2 motion
2.01 speed, velocity, and acceleration
speed is a measure of how fast something is travelling.
speed = total distance
total time
d
s t
velocity is speed in a given direction.
the only difference between velocity and speed is that velocity has a direction, and
so is a vector quantity.
average velocity = displacement *displacement is the distance moved in a straight
time line, in a given direction, from the starting point.
acceleration is the change in velocity per second and is measured in m/s2.
acceleration = change of velocity
time taken
*if an object has an acceleration of 10m/s2 it means that the
v-u velocity of the object changes by 10m/s every second.
a t v = final velocity ; u = initial velocity
a negative acceleration is called a deceleration or retardation.
a uniform acceleration means a constant (steady) acceleration.
1
, amber
2.02 motion graphs
distance-time graph
-a distance-time graph shows how the distance of an object (from a point) varies
over time.
-the speed of an object can be calculated from the gradient of a distance-time graph.
speed = distance
time
-in a distance-time graph, the gradient of the line is equal to the speed of the object.
the greater the gradient (and the steeper the line) the faster the object is moving.
120
constant speed
90 acceleration
distance (m)
60 stationary
30 moving backwards
0
0 1 2 3 4
time (s)
if an object is accelerating or decelerating, its speed can be calculated at any
particular time by:
-drawing a tangent to the curve at that time
-measuring the gradient of the tangent
gradient = vertical change (A)
horizontal change (B)
object moving at a constant speed but
changing direction continually is also
accelerating. velocity, a vector quantity,
changes if either the magnitude or the
direction changes.
2
general physics
1.2 motion
2.01 speed, velocity, and acceleration
speed is a measure of how fast something is travelling.
speed = total distance
total time
d
s t
velocity is speed in a given direction.
the only difference between velocity and speed is that velocity has a direction, and
so is a vector quantity.
average velocity = displacement *displacement is the distance moved in a straight
time line, in a given direction, from the starting point.
acceleration is the change in velocity per second and is measured in m/s2.
acceleration = change of velocity
time taken
*if an object has an acceleration of 10m/s2 it means that the
v-u velocity of the object changes by 10m/s every second.
a t v = final velocity ; u = initial velocity
a negative acceleration is called a deceleration or retardation.
a uniform acceleration means a constant (steady) acceleration.
1
, amber
2.02 motion graphs
distance-time graph
-a distance-time graph shows how the distance of an object (from a point) varies
over time.
-the speed of an object can be calculated from the gradient of a distance-time graph.
speed = distance
time
-in a distance-time graph, the gradient of the line is equal to the speed of the object.
the greater the gradient (and the steeper the line) the faster the object is moving.
120
constant speed
90 acceleration
distance (m)
60 stationary
30 moving backwards
0
0 1 2 3 4
time (s)
if an object is accelerating or decelerating, its speed can be calculated at any
particular time by:
-drawing a tangent to the curve at that time
-measuring the gradient of the tangent
gradient = vertical change (A)
horizontal change (B)
object moving at a constant speed but
changing direction continually is also
accelerating. velocity, a vector quantity,
changes if either the magnitude or the
direction changes.
2
