3. Physics is the science of matter
and energy and their interaction
with each other. It basically tries
to explain the laws and principles
that govern the materials in the
universe. It is the most
fundamental of all the sciences
since it involves the most
fundamental quantities the
universe has.
4. Learning objective:
Identify the differences between
scalar and vector quantity.
Recognize the meaning of basic
terms in describing the separation
between two points: distance and
displacement.
Identify the differences between
displacement and distance.
6. MOTION
• Motion of an object can be divided into two
categories. The quantity is either a vector or
scalar.
• SCALAR quantity- are quantities that are fully
described by a magnitude alone.
• VECTOR quantity- are quantities that are fully
described by both a magnitude and a direction.
7. L4:How do object move?
Distance and Displacement
Distance refers to the total path
length traveled between two points. It
is scalar quantity that has magnitude
but with no direction.
Displacement refers to the change in
position of a body relative to some
reference point. It is a vector quantity
that has both magnitude and
direction.
8. Figure 4.1
The total distance and displacement of a girl from a lamp
past.
In Figure 4.1A, a girl walks 3.5 m away
from a lamp post.
The total distance traveled by the girl is
3.5m and the total displacement is 3.5m
to the east.
9. In Figure 4.1B, the girl returns
and moves 2.0m to the west.
The total distance traveled is
now 5.5m which is the sum of
3.5m and 2.0m. The total
displacement is 1.5m east
which is the vector sum of 3.5
m east and 2.0 west. This is
the shortest straight-line
distance between two points.
10. Check your understanding
• Consider the following quantities below.
Categorize each quantity as being a VECTOR
or a SCALAR.
Quantity Category
a. 5m
b. 30m/sec, East
c. 5 mi., North
d. 20 Km
e. 256 mi
11. To test your understanding of this
distinction, consider the motion
depicted in the diagram below.
Situation:
A Physics teacher walks 4 meters East, 2
meters South, 4 meters West, and finally 2
meters North.Calculate the distance and
displacement.
12. To test your understanding of this distinction, consider the motion
depicted in the diagram below.
Situation:
A Physics teacher walks 4 meters East, 2 meters South, 4 meters West, and finally 2 meters
North.Calculate the distance and displacement.
A. distance:
Given:
d1=4m
d2= 2m
d3= 4m
d4= 2m
Formula:
dT= d1+d2+d3+d4
Solution:
dT: 4m+2m+4m+2m
Final Answer: 12m
A. displacement:
Given:
d1=4m,E
d2= 2m,S
d3= 4m,W
d4= 2m,N
Formula:
dT= d1+d2+d3+d4
Solution:
dT: 4m,E+(-2m,S)+(-
4m,W)+2m,N
Final Answer: 0m
13. Evaluation
• The diagram above shows the position of a cross-country skier at various times. At each of the
indicated times, the skier turns around and reverses the direction of travel. In other words, the
skier moves from A to B to C to D.
• Determine the resulting displacement and distance.
14. Evaluation
• Consider a football coach pacing back and forth along
the sidelines. The diagram above shows several of
coach’s positions at various times. At each marked
position, the coach makes a “U-turn” and moves in the
opposite direction. In other words, the coach moves
from position A to B to C to D. Determine displacement
and distance.
Editor's Notes
The universe is vast or very enormous and complicated. In order for us to understand and know more about it, different scientists and philosophers give/generate various experimental observations and develop different theories/artifacts and even further studies. Some occurrences in the physical world had been observed and became the bases for formulation of laws. The work of the scientists and philosophers have made remarkable impact in our understanding of the different occurrences in nature and became the bases for formulating laws and principles. Nowadays, these laws and principles help us to see beyond the physical world of matter-its motion and behavior in small distances and even in cosmological scale.
Physics comes from the greek word “physikos” meaning natural
Study of matter and energy and their relationship
How can we tell that something is moving or not? When we are just standing or simply lying on our bed, can we say that we are moving? Of course we will quickly say, “No, we are not moving. We are at rest”. This is because you don’t change your position. However, if we will consider the reference of motion, we are actually moving. The Earth is moving. It is rotating and revolving. If we consider this as our reference of motion, then if we are standing or lying on bed, we are also considered to be in motion. We are moving along with the Earth. In the same manner, a passenger is not in motion with respect to the vehicle he is in. However, he is in motion with respect to the road. This is because motion is relative to a frame of reference. Thus we can define motion as a continuous change of position with respect to a certain frame of reference.
The main difference between the two is that scalar quantity tells the magnitude while vector tells the magnitude and direction.
Let us also distinguish the two important terms in describing motion – distance and displacement. These two have specific meanings that are necessary in quantifying speed and velocity of a moving body.
Imagine class the you are ask by you nanay or tatay to buy magic sarap at the near sari-sari store in your house and these dot or connected dots shows the way from your house (HERE) to the sari-sari store (HERE)
1.Scalar
2.Vector
3.Vector
4. Scalar
5.Scalar
Even though the physics teacher has walked a total distance of 12 meters, his displacement is 0 meters. During the course of his motion, he has “covered 12 meters ground” (distance=12 m). Yet when he finished walking, he is not “out of place”. Displacement, being vector quantity, must give attention to direction. The 4 meters East cancels the 4 meters West; and the 2 meters South cancels the 2 m North. Vector quantities such as displacement are direction aware.
Even though the physics teacher has walked a total distance of 12 meters, his displacement is 0 meters. During the course of his motion, he has “covered 12 meters ground” (distance=12 m). Yet when he finished walking, he is not “out of place”. Displacement, being vector quantity, must give attention to direction. The 4 meters East cancels the 4 meters West; and the 2 meters South cancels the 2 m North. Vector quantities such as displacement are direction aware.
The skier covers a distance of (180+140+100)=420meters and has displacement of 140m, rightward.
The coach covers a distance of 35 yds+20+40yds=95yards and has displacement of 55 yards, left.
