Unit 3: Motion and movement. 2º ESO.

1. UNIT 3: MOTION
AND MOVEMENT

2. WHAT IS THE
MOVEMENT?
 Movement is the change of position of an object in
relation to a fixed point in space.
 In physics, motion is the change of location or
position of an object with respect to time.

3. MOTION
CHARACTERISTICS
 The main characteristics are the following ones:
position, trajectory, distance travelled,
displacement, time taken, speed and
acceleration.
 Position is precisely where an object is located.
 Trajectory is the path that a moving object follows
through space. It can be rectilinear, circular,
parabolic etc . Ex: a ball thrown into a basket is
parabolic or the hands of a watch is circular.

4.  The distance travelled is the length of the
trajectory made by the moving object from the initial
position to the final position.
 The displacement (D) is the distance, measured in
straight line, between the initial position(Xi) and the
final position (Xf). D=Xf-Xi

5.  Speed is the distance travelled per unit of time.
 Average speed (Vm) is calculated dividing the distance
travelled by the time spent.
Vm= distance travelled
time spent
The unit used to measure the speed in the SI is metres per
second. (m/s)

6. UNIFORM LINEAR
MOTION
A body has a uniform linear motion if the trajectory is
a straight line and the speed is constant.
d= v x t time
Distance Distance-time graph
travelled speed
Speed-time graph

7. ACCELERATION
 If speed changes in a movement, it is an accelerated
motion.
 Acceleration is how fast the speed of an object is
changing. It is calculated dividing the variation of
speed by the time spent at this variation.
vfinal - vinitial
a
tfinal - tinitial
 The unit used in the SI is metres per square second
(m/s2)

8. UNIFORMLY VARIED
MOTION
 The speed varies in a uniform way. Ex: A train
starting off o stopping.

9. Motion
can be what can change the speed of
objects or can deform them, are the
Uniform motion
Change of position with respect to another one
that we consider as fixed.
Speed doesn’t
change
Trajectory Position Distance travelled Speed Acceleration
can be
The acceleration is
It is equal to the defined as the ratio
subtraction between between what the
Accelerated motion
two positions speed has changed
Rectilinear and the time
Circular It is the ratio between elapsed to occur
Parabolic It is where the distance travelled that change
Elliptical an object and the time elapsed
Speed changes Hyperbolic is located to do it Forces

10. ACTIVITY 1
An athlete can run long distances at 4 metres
per second. How far can she run in?
c)50 seconds
e)3 minutes
g)1 hour
i)2 hours and a half

11. ACTIVITY 2
Andrew rows at an average speed of 2 metres per
second.
a)How long does it take him to
row:
Speed Distance
• 70 m Time
• 800 m Distance Speed x Tim
e
• 1 km and a half
Time Distance
b) How far can Andrew row in: Speed
• 12 seconds
• 3 minutes and a half
• 4 hours

12. ACTIVITY 3
A snail moves 5 m in 2 hours. If it moves at the
same speed all the time, calculate:
a)The time it takes to move 20 m
c) The distance it would move in 3 hours and a half
e)The time it takes to move 1 m
g)The distance it moves in 15 minutes

13. ACTIVITY 4
John can type 960 words in 20 minutes.
Calculate his typing speed in:
c)Words per minute
d)Words per hour

14. ACTIVITY 5
A car is at rest and accelerates with an
acceleration of 5 m/s2 during 10 seconds, we can
say that:
A. It has an average speed of 50 m/s.
C. It travels a distance of 50 m.
E. Its final speed is 50 m/s.
G. It travels a distance of 2 m.

15. ACTIVITY 6
The graph represents data of positions and times of the
movement of an object.
A. Is it an uniform motion or an
accelerated motion? Justify your
answer.
s (m) B. The position of the object at 2
seconds from when the movement
started. The position of the object
at 6 seconds.
C. Speed at the interval 2-6 seconds.
D. The position of the object at 4
seconds from when the movement
started. The position of the object
at 10 seconds.
E. Speed at the interval 4-10
t (s) seconds.
F. How has the trajectory been?

16. ACTIVITY 7
Given the following values tables, answer the following questions.
Values table A Values table B
s (m) t (s) s (m) t (s) A. Draw the graph s/t of each
2 0 0 0 movement.
4,5 1 2 1
C. Calculate the average speed in
7 2 5 2
the first five seconds for each
9,5 3 9 3 values table.
12 4 14 4
14,5 5 20 5 E. Calculate the average speed in
17 6 27 6 the time elapsed from the
second five to the second ten
19,5 7 35 7
for each values table.
22 8 44 8
24,5 9 54 9 G. Indicate the type of movement
27 10 65 10 represented in each graph.