WHAT IS MOTION?
●Motion: The act or process of changing position or place.
● We encounter motion every day!
● Think about: walking, a car driving, a fan spinning, a door opening.
But how do we describe these
different types of motion?
3.
TRANSLATIONAL MOTION
Motionwhere the entire body
moves from one place to another
without any rotation.
Key Characteristic: All points on
the body travel the same
distance, in the same direction,
and at the same time.
This applies to both rectilinear
(straight-path) and curvilinear
(curved-path) movements.
4.
LINEAR QUANTITIES (forTranslational
Motion)
The change in position of an object
(how far and in what direction it moved
from its start point).
LINEAR DISPLACEMENT
If you walk 5 meters east from
your desk, your linear
displacement is 5 meters East. It
doesn't matter if you took a
winding path; the net change in
position is 5 meters East.
5.
LINEAR QUANTITIES (forTranslational
Motion)
LINEAR VELOCITY
A motorcycle traveling at 60
km/h North has a linear
velocity. If it maintains that
speed and direction, its
velocity is constant.
The rate at which an object
changes its position (speed with
direction).
6.
LINEAR QUANTITIES (forTranslational
Motion)
LINEAR ACCELERATION
Speeding up: A car pressing the gas pedal to go from 0 to 60 mph.
Slowing down: A bicycle applying brakes to come to a stop.
Changing direction: A car turning a corner at a constant speed is
still accelerating because its direction of velocity is changing.
The rate at which an object's
velocity changes over time
(speeding up, slowing down, or
changing direction).
7.
LINEAR QUANTITIES (forTranslational
Motion)
The change in position of an object (how far and in
what direction it moved from its start point).
LINEAR DISPLACEMENT
The rate at which an object changes its position
(speed with direction).
LINEAR VELOCITY
The rate at which an object's velocity changes over
time (speeding up, slowing down, or changing
direction).
LINEAR ACCELERATION
8.
TRANSLATIONAL MOTION EXAMPLES
•A sprinter running from the starting line to the
finish line.
• A dog running along a curved road at a slow
pace.
• A plane flying a curved path, speeding up upon
takeoff and slowing down for landing.
• A fish swimming in a straight line from a rock to
another rock.
9.
ROTATIONAL MOTION
Occurswhen a body turns or spins
around an axis.
Key Characteristic: different points on
the body travel different linear
distances and in varying linear
directions, but all points rotate
through the same angle in the same
time.
The axis of rotation can be within the
body (like a spinning top) or outside
the body (like the Earth orbiting the
sun, where the Earth itself is rotating
while translating).
10.
ANGULAR QUANTITIES (forROTATIONAL MOTION)
Angle made by a body while
moving in a circular path. It tells
you how much an object has
rotated. It's measured in
radians, degrees, or revolutions.
ANGULAR DISPLACEMENT
A door opening 90 degrees has
an angular displacement of
π/2 radians.
11.
ANGULAR QUANTITIES (forROTATIONAL MOTION)
How fast an object rotates or
revolves relative to another
point. It's the rate of change of
angular displacement.
ANGULAR VELOCITY
An electric fan spinning at
1200 revolutions per minute
(RPM) has a high angular
velocity.
12.
ANGULAR QUANTITIES (forROTATIONAL MOTION)
Rate with which angular velocity
changes with time. It means the
object is speeding up or slowing
down its spin.
ANGULAR ACCELERATION
A merry-go-round starting
from rest and gradually
spinning faster experiences
angular acceleration.
13.
ROTATIONAL MOTION EXAMPLES
•A door being opened.
• An electric fan spinning very fast.
• A merry-go-round going from rest, to a slow
spin, to a faster spin.
• The Earth spinning about its axis.
14.
Translational vs. RotationalMotion: Comparison
Feature Translational Motion Rotational Motion
Movement Entire body changes location Body spins or turns around an axis
Linear Disp. All points have equal linear displacement
Points have varying linear displacements
(farther points move more)
Direction All points travel in the same direction
Points travel in varying linear directions
(tangential)
Linear Velocity All points travel with the same linear velocity
Points travel with different linear velocities
(faster farther out)
Linear Accel.
All points travel with the same linear
acceleration
Points travel with varying linear
accelerations
Quantities Linear displacement, velocity, acceleration Angular displacement, velocity, acceleration
15.
Combined Motion
● Anobject can exhibit both types of motion simultaneously.
o A ball spinning while "flying"
through the air.
o A stone rolling downhill.
o The wheels of a moving
vehicle.
o NASA's Mars Helicopter: This
incredible machine moves
forward across the Martian
landscape (translational) while
its rotors spin rapidly to provide
lift (rotational).
16.
APPLICATIONS IN ENERGOMICDESIGN
• Swivel Chairs
• Adjustable Desks/Monitors
• Ergonomic Tools: Many hand tools are designed with consideration for natural
joint movements, often incorporating rotational elements to reduce repetitive
strain. For instance, a screwdriver with a rotating handle allows for continuous
turning without re-gripping.
This field focuses on designing products and
environments to optimize human well-being and
overall system performance. It's about making things
fit people, not forcing people to fit things.
Energomics
Examples
17.
Safety: wecan design safer
environments and equipment.
Efficiency: It leads to machines that
operate with less energy waste and
greater output.
Innovation: Development of new
ergonomic products that enhance
comfort and productivity.
Daily Life: Helps us make sense of the
world around us.
WHY IS UNDERSTANDING MOTION
IMPORTANT?
18.
SUMMARY
• We've exploredtranslational motion, where the entire body moves without
rotation, described by linear quantities like displacement, velocity, and
acceleration.
• We've also delved into rotational motion, where a body spins around an axis,
described by angular quantities such as angular displacement, angular velocity,
and angular acceleration.
• Crucially, we've seen that many real-world scenarios involve combined motion,
where objects both translate and rotate.
• These concepts are fundamental to understanding physics and have wide-
ranging applications in human movement, engineering, and everyday design,
contributing to safety, efficiency, and innovation.
Editor's Notes
#2 These examples highlight that motion isn't just one thing. There are different ways objects can move, and understanding these differences is key to describing the world around us.
#3 The crucial part is that the object's orientation doesn't change relative to its path.
#9 The crucial part is that the object's orientation doesn't change relative to its path.
#10 The crucial part is that the object's orientation doesn't change relative to its path.
#11 The crucial part is that the object's orientation doesn't change relative to its path.
#12 The crucial part is that the object's orientation doesn't change relative to its path.
#16 Understanding motion helps engineers and designers create tools and environments that reduce strain, prevent injuries, and improve comfort and efficiency.
#17 Safety: we can design safer environments and equipment. For example, helmets are designed not only to absorb linear impact but also to mitigate rotational forces that can cause traumatic brain injuries.
Efficiency: Optimizing machine and human performance is a key benefit. In sports, understanding biomechanics helps athletes move more efficiently. In industrial design, it leads to machines that operate with less energy waste and greater output.
Innovation: These fundamental concepts drive innovation. From advanced robotics that mimic human movement to the development of new ergonomic products that enhance comfort and productivity, the principles of motion are at the core.
Daily Life: Beyond specialized fields, understanding motion helps us make sense of the world around us, from predicting the path of a thrown ball to appreciating the engineering behind a smoothly operating car.
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