MOVEMENT IN ONE
DIMENSION
Sutherland High School
CAPS
POSITION
THIS IS THE PLACE WHERE AN OBJECT IS RELATIVE TO A REFERENCE POINT.
A REFERENCE POINT IS A POINT FROM WHICH THE POSITON OF THE OBJECT IS MEASURED.
SYMBOL: 𝑥
SI UNIT: 𝑚
VECTOR
3m 1m
Example 1
Example 2
5m3.7m
1.3m
FRAMES OF REFERENCE
• Frames of reference gives a better description of motion.
• It depends where you are at that moment when using the reference point.
• The most common frame of reference for most of our movements is the earth.
• E.g. cars on the highway, throwing ball on train etc.
The difference: 𝑥 and ∆𝑥
•𝑥 = the actual position.
•∆𝑥 = change in position.
DISTANCE
DISTANCE IS THE TOTAL LENGTH OF THE ROUTE.
SYMBOL: 𝒅
Si Unit: 𝒎
SCALAR QUANTITY
DISPLACEMENT IS THE SHORTEST
DISTANCE BETWEEN START AND
FINISH.
SYMBOL IS 𝒙 AND 𝒚SI UNIT: 𝒎VECTOR QUANITY
DISPLACEMENT
Study definitions on
pg. 164
Example 3
10km east
6km west
WHAT IS THE CROWS DISPLACEMENT?
WHAT DISTANCE DID THE CROW FLY?
Example 4SOLDIERS GO ON A MARCH IN THE
DESERT. THEY FIRST WALK 6KM WEST,
REST A BIT, THEN 10KM EAST, REST A BIT,
AND THEN 2KM WEST.
1. CALCULATE THE DISTANCE COVERED.
2. CALCULATE THE DISPLACEMENT.
3. CALCULATE THEIR POSITON AT THE
SECOND REST STOP.
HOMEWORKEXERCISE 15 PG. 168-169
SPEED• The rate at which an object covers a distance.
• Distance and time is scalar – speed is scalar.
• 𝑣 =𝐷
∆𝑡
• Constant / uniform speed = speed does not change. This means that it covers equal distances in equal time intervals. This is not a common occurrence.
• Average speed = total distance divided by total time. This does not tell you how fast you are going at any moment in time.
• 𝑣𝑎𝑣𝑒 =𝐷
∆𝑡or 𝑣 =
𝐷
∆𝑡
Example 1
THE CROW FLIES IN 10KM IN 2 HOURS.
WHAT IS THE CROW’S SPEED?
VELOCITY• The rate of change of an objects position or the displacement
divided by the time taken.
• Displacement is a vector = velocity is a vector.
• 𝑣 =∆𝑥
∆𝑡
• Constant / uniform velocity = magnitude and direction must be the same. Travels in a straight line.
• If speed changes = velocity changes.
• If direction changes = velocity changes.
• Average velocity = total displacement divided by total time.
• 𝑣𝑎𝑣𝑒 =∆𝑥
∆𝑡or 𝑣𝑎𝑣𝑒 =
∆𝑦
∆𝑡
Example 2
6km west
A CROW FLIES 6KM WEST AND DOES SO IN 7MIN.
WHAT IS THE CROWS VELOCITY?
Example 3
10km east
6km west
A CROW FLIES 10KM EAST FOR 1 HOUR
AND THEN TURNS AROUND AND FLIES
6KM WEST FOR 40MIN.
WHAT IS THE CROW’S SPEED FOR THE TOTAL JOURNEY?
WHAT IS THE CROW’S VELOCITY FOR THE TOTAL JOURNEY?
Pick a
partner
and
solve.
CONVERSION
𝑘𝑚. ℎ−1 𝑚. 𝑠−1
÷ 𝟑. 𝟔
x 𝟑. 𝟔
homeworkExercise 16 pg. 175-176
ACCELERATION• The rate of change of an objects velocity.
• Velocity is a vector = acceleration is a vector.
• 𝑎 =∆𝑣
∆𝑡=
𝑣𝑓−𝑣𝑖
∆𝑡
• Constant / uniform acceleration = there is a constant increase in velocity in every equal time interval.
• Acceleration can be positive or negative.
• If the acceleration and velocity is in the same direction – the object is speeding up.
• If the acceleration and velocity is in the opposite direction – the object is slowing down
Example 4
A CAR STARTS FROM REST AT A STOP STREET. AFTER 𝟓𝒔 THE CAR HAS A
VELOCITY OF 𝟕𝒎𝒔−𝟏 . CALCULATE THE ACCELERATION OF THE CAR.
WHILE TRAVELLING AT A SPEED OF 𝟏𝟎𝒎. 𝒔−𝟏 ON A STRAIGHT ROAD, THE
CAR SUDDENLY HAS TO STOP FOR A RED LIGHT. IT TAKES THE CAR 6
SECONDS TO COME TO A STOP. CALCULATE THE ACCELERATION.
TICKER TIMERSExercise 17 pg. 189-192
IMPORTANT FACT: MOTION FOR TICKER TIMERS CAN ONLY BE LEFT AND RIGHT. NOT NORTH, EAST, SOUTH OR WEST!