Velocity: The Key to Motion
Definition: Velocity
is the speed at which something moves in
one direction.
e.g. The speed of a car traveling north on a major freeway and
the speed a rocket launching into space can both be measured
using
velocity
.
Velocity
is the prime indicator of the position as well as the
rapidity of the object.
Velocity
can be
defined
as the
displacement of the object in unit time.
The
velocity
of an object is the rate of change of its position
with respect to a frame of reference, and is a function of
time.
Velocity
is equivalent to a specification of an object's speed
and direction of motion (e.g. 60 km/h to the north).
The
instantaneous velocity
of an object is the limit of
the average
velocity
as the elapsed time approaches
zero, or the derivative of x with respect to t:
v(t)=ddtx(t). v ( t ) = d d t x ( t ) . Like
average
velocity
,
instantaneous velocity
is a vector
with dimension of length per time.
Velocity
(v) is a vector quantity that measures
displacement (or change in position, (Δs) over the
change in time (Δt), represented by the
equation
v = Δs / Δt
Speed
, being a scalar quantity,
is
the rate at which an
object covers distance.
On the other hand,
velocity is
a vector quantity;
it
is
direction-aware.
Velocity is
the rate at which the
position changes. The
average velocity is
the
displacement or position change (a vector quantity) per
time ratio.
Therefore, speed and velocity are not same.
Speed
is a scalar,
velocity
is a vector.
We
care because
it gives us more information. In three dimensional
space
velocity
is expressed with three numbers.
Velocity
includes information about direction as well
as
speed
(magnitude of
velocity
).
So we need velocity to specify the direction which
speed cannot.
Velocity
comes with direction, it indicates a speed at a
direction.
If
velocity
becomes
negative
, it is that speed in the
opposite direction.
Zero velocity
is essentially no movement. What this
means is that your change in position from time a to
time b is
zero
.
This happens when you throw an object to the sky. Just
before it falls, when there is no force moving it
upwards, it will remain motionless and its
velocity
will
be
zero
.
a car moving.
a ball being dropped.
the earth moving around the sun.
A body is said to have
uniform velocity
if it covers
equal distance in equal intervals of time in a particular
direction.
i.e. s/t = constant
When a truck travels in equal distances in equal
intervals of time then we say that the
body
has got a
uniform velocity.
In the above example a truck is traveling at 5 miles in
all the positions at A, B, and C and all in the intervals
of 5 minutes each.
When an object covers unequal distances in equal
intervals of time in a specified direction, or if the
direction of motion changes, it is said to be moving
with a
non
-
uniform
or variable
velocity
.
e.g., revolving fan at a constant speed has
variable
velocity
.
UNIFORM VELOCITY
: when an object is moving
in
a
straight line, without any acceleration. No change
in
speed
or direction is experienced.
CONSTANT VELOCITY
: when the
speed
of an
object has not changed even though the object may
have experienced a change in direction (zero
acceleration).
The definition of
acceleration
is: that is defined as the
rate at which an object changes its velocity. An object
is
accelerating
if it is changing its velocity.
Acceleration
is the rate of change of velocity.
Usually,
acceleration means
the speed is changing, but
not always. When an object moves in a circular path at
a constant speed, it is still
accelerating
, because the
direction of its velocity is changing.
Any change in the velocity of an object results in
an
acceleration
:
o
increasing speed (what people usually mean when they
say
acceleration
)
o
decreasing speed (also called deceleration or
retardation ),
o
or changing direction (called centripetal
acceleration
).
Acceleration
(a) is the change in velocity (Δv) over the
change in time (Δt), represented by the equation:
a = Δv/Δt.
This allows you to measure how fast velocity changes
in meters per second squared (m/s^2).
Acceleration
is a vector quantity
The
SI unit of acceleration
is the metre per second
squared (m s
−2
); or "meter per second per second", as
the velocity in meters per second changes by
the
acceleration
value, every second.
Velocity
is the rate of change of position with respect
to time, whereas
acceleration
is the rate of change
of
velocity
. Both are vector quantities (and so also have
a specified direction), but the units of
velocity
are
meters per second while the units of
acceleration
are
meters per second squared.
Therefore, velocity and acceleration are not same.
Whenever
you
accelerate in one direction,
you feel
a
gravity-like sensation pulling
you
in the opposite
direction. That sensation is sometimes called a
"fictitious force," despite the fact that it isn't a force at
all. The
feeling
of
acceleration
is really just your
inertia acting to impede your
acceleration
.
When the car slows down.
When you fall off a bridge.
The car turning at the corner.
o
All are the
examples of acceleration
because the
direction is changing. The quicker one turns, the greater
the
acceleration
.
“Yes” a
body can have zero velocity
and
can
still
accelerate simultaneously
.So, at the highest point for a
body
thrown
upwards,
velocity
is zero and
acceleration
is equal to g
(9.8 ms^-2) in downward direction.
Velocity is a vector with speed and direction, any
change is that is acceleration.
The
earth
is
accelerating
because it's direction is
changing. Yet it's speed around the sun remains more or
less constant, changing slightly as
earth
moves from its
perihelion to aphelion.
Earth
moves very fast. It spins (rotates) at a speed of
about 1,000 miles (1600 kilometers) per hour and orbits
around the Sun at a speed of about 67,000 miles
(107,000 kilometers) per hour.
We
do not
feel
any of
this motion because these speeds are constant.
An object in constant
acceleration
has a
linear
velocity
vs. time graph; that is, the slope of the
graph is constant.
Initial velocity
is independent of the slope of the
graph; that is, the
acceleration
. An object thrown
downward still accelerates after release at the same rate
as an object that is dropped.
If the
velocity is
constant however, the
acceleration is
zero
(because the
velocity
isn't changing over time).
Although at an instant in time it
is
possible to
have
zero velocity
whilst
accelerating.
For example, if you drop an object at the instant you
release it has
zero velocity
but it
is accelerating
.
Yes, a
body can have positive velocity and negative
acceleration
at the same time.
For example when a lift goes upwards from 4th to 8th
floor considering base as origin and
get
stopped then
velocity is positive while
acceleration
is
negative
.
Freefall
is a special case of motion with
constant
acceleration
, because
acceleration
due to gravity is
always
constant
and downward. This is true even when
an object is thrown upward or has zero
velocity.
Acceleration
from gravity is
always
constant
and downward, but the direction and
magnitude of velocity change.
Yes, an
object
that was set in motion in the past by
some force, but that is no longer being acted on by a
net force, is
moving
but with
zero acceleration
, i.e. it
is
moving
at constant velocity.
Velocity is the speed and direction at which an object moves, indicating both its position and rapidity. It is crucial for measuring the rate of change of an object's position over time and differentiates from speed as a vector quantity. This comprehensive guide delves into the concepts of velocity, including instantaneous velocity, vector nature, units of measurement, and the distinction between speed and velocity.
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Presentation Transcript
Definition: Velocity is the speed at which something moves in one direction. e.g. The speed of a car traveling north on a major freeway and the speed a rocket launching into space can both be measured using velocity. Velocity is the prime indicator of the position as well as the rapidity of the object. Velocity can be defined as the displacement of the object in unit time. The velocity of an object is the rate of change of its position with respect to a frame of reference, and is a function of time. Velocity is equivalent to a specification of an object's speed and direction of motion (e.g. 60 km/h to the north).
The instantaneous velocity of an object is the limit of the average velocity as the elapsed time approaches zero, or the derivative of x with respect to t: v(t)=ddtx(t). v ( t ) = d d t x ( t ) . Like average velocity, instantaneous velocity is a vector with dimension of length per time.
Velocity (v) is a vector quantity that measures displacement (or change in position, ( s) over the change in time ( t), represented by the equation v = s / t
Quantity : Vector is a vector quantity. Units: The SI unit for velocity is Meter per second (m? ?)
Speed, being a scalar quantity, is the rate at which an object covers distance. On the other hand, velocity is a vector quantity; it is direction-aware. Velocity is the rate at which the position changes. The average velocity is the displacement or position change (a vector quantity) per time ratio. Therefore, speed and velocity are not same.
Speed is a scalar, velocity is a vector. We care because it gives us more information. In three dimensional space velocity is expressed with three numbers. Velocity includes information about direction as well as speed (magnitude of velocity). So we need velocity to specify the direction which speed cannot.
Velocity comes with direction, it indicates a speed at a direction. If velocity becomes negative, it is that speed in the opposite direction.
Zero velocity is essentially no movement. What this means is that your change in position from time a to time b is zero. This happens when you throw an object to the sky. Just before it falls, when there is no force moving it upwards, it will remain motionless and its velocity will be zero.
a car moving. a ball being dropped. the earth moving around the sun.
A body is said to have uniform velocity if it covers equal distance in equal intervals of time in a particular direction. i.e. s/t = constant
When a truck travels in equal distances in equal intervals of time then we say that the body has got a uniform velocity. In the above example a truck is traveling at 5 miles in all the positions at A, B, and C and all in the intervals of 5 minutes each.
When an object covers unequal distances in equal intervals of time in a specified direction, or if the direction of motion changes, it is said to be moving with a non-uniform or variable velocity. e.g., revolving fan at a constant speed has variable velocity.
UNIFORM VELOCITY: when an object is moving in a straight line, without any acceleration. No change in speed or direction is experienced. CONSTANT VELOCITY: when the speed of an object has not changed even though the object may have experienced a change in direction (zero acceleration).
The definition of acceleration is: that is defined as the rate at which an object changes its velocity. An object is accelerating if it is changing its velocity. Acceleration is the rate of change of velocity. Usually, acceleration means the speed is changing, but not always. When an object moves in a circular path at a constant speed, it is still accelerating, because the direction of its velocity is changing.
Any change in the velocity of an object results in an acceleration: o increasing speed (what people usually mean when they say acceleration) o decreasing speed (also called deceleration or retardation ), o or changing direction (called centripetal acceleration ).
Acceleration (a) is the change in velocity (v) over the change in time ( t), represented by the equation: a = v/ t. This allows you to measure how fast velocity changes in meters per second squared (m/s^2).
Acceleration is a vector quantity The SI unit of acceleration is the metre per second squared (m s 2); or "meter per second per second", as the velocity in meters per second changes by the acceleration value, every second.
Velocity is the rate of change of position with respect to time, whereas acceleration is the rate of change of velocity. Both are vector quantities (and so also have a specified direction), but the units of velocity are meters per second while the units of acceleration are meters per second squared. Therefore, velocity and acceleration are not same.
Whenever you accelerate in one direction, you feel a gravity-like sensation pulling you in the opposite direction. That sensation is sometimes called a "fictitious force," despite the fact that it isn't a force at all. The feeling of acceleration is really just your inertia acting to impede your acceleration.
When the car slows down. When you fall off a bridge. The car turning at the corner. o All are the examples of acceleration because the direction is changing. The quicker one turns, the greater the acceleration.
Yes a body can have zero velocity and can still accelerate simultaneously .So, at the highest point for a body thrown upwards, velocity is zero and acceleration is equal to g (9.8 ms^-2) in downward direction.
Velocity is a vector with speed and direction, any change is that is acceleration. The earth is accelerating because it's direction is changing. Yet it's speed around the sun remains more or less constant, changing slightly as earth moves from its perihelion to aphelion.
Earth moves very fast. It spins (rotates) at a speed of about 1,000 miles (1600 kilometers) per hour and orbits around the Sun at a speed of about 67,000 miles (107,000 kilometers) per hour. We do not feel any of this motion because these speeds are constant.
An object in constant acceleration has a linear velocity vs. time graph; that is, the slope of the graph is constant. Initial velocity is independent of the slope of the graph; that is, the acceleration. An object thrown downward still accelerates after release at the same rate as an object that is dropped.
If the velocity is constant however, the acceleration is zero (because the velocity isn't changing over time). Although at an instant in time it is possible to have zero velocity whilst accelerating. For example, if you drop an object at the instant you release it has zero velocity but it is accelerating.
Yes, a body can have positive velocity and negative acceleration at the same time. For example when a lift goes upwards from 4th to 8th floor considering base as origin and get stopped then velocity is positive while acceleration is negative.
Freefall is a special case of motion with constant acceleration, because acceleration due to gravity is always constant and downward. This is true even when an object is thrown upward or has zero velocity. Acceleration from gravity is always constant and downward, but the direction and magnitude of velocity change.
Yes, an object that was set in motion in the past by some force, but that is no longer being acted on by a net force, is moving but with zero acceleration, i.e. it is moving at constant velocity.
