Motion in straight line: Velocity & Acceleration | POINT classical mechanics
Motion in straight line: Velocity vs Acceleration
translational motion: is movement that has start and end point
Velocity is the displacement traveled by the body in a unit of time.
It's vector quantity (It's determined by both magnitude and direction)
It is positive when the body moves in a certain direction, and negative if it moves in the opposite direction.
*when body moves in straight line and with regular acceleration, we can calculate the average velocity from this equation:
The motion:
so When the position of a body changes over time, the body is said to have moved.
The motion of this body can be represented by taking a series of successive images at equal time intervals and assembling these images into a single image known as a motion diagram.
Any body is treated as a point, neglecting the internal structure of the body, its size and geometric shape, even if the body is a person or a galaxy.
Types of motion:
1. Translational motion
2. periodic motion
example: 1. motion in a straight line (like train's motion)
2. Projectile motion (like the cannonball moving)
 |
| cannonball moving |
 |
| train's motion |
periodic motion: is movement that repeating itself at equal intervals on time
EX : 1. Vibrational motion (like Pendulum movement, string movement of musical instruments)
2. motion in a circle (like moon movement around the earth, Motion of a weight tied to a string and moving in a circular path
 |
| string movement of musical instruments |
 |
| pendulum movement |
 |
| moon movement around the earth |
 |
| motion of a weight tied to a string and moving in a circular path |
Now we'll talk about concepts related to motion in a straight line.
the Velocity:
if a car moved from position1 to position2 (specific displacement Δd [d2-d1]) and from time 1 to time 2 (specific time Δt [t2-t1]), So velocity determined by this equation: v=Δd/Δt
The unit of Velocity is: m/s or km/h
its dimensional formula is L.T
So the Velocity is the quantity that tells you how much distance an object has traveled in a specific time (a second or an hour, for example).
Velocity can expressed in two ways
1. Velocity
2. Speed
Speed is the distance traveled by the body in a unit of time
It's scalar quantity (it's determined by magnitude only)
it's Always positive
It's scalar quantity (it's determined by magnitude only)
it's Always positive
It's vector quantity (It's determined by both magnitude and direction)
It is positive when the body moves in a certain direction, and negative if it moves in the opposite direction.
*The term velocity that used in equations means vector velocity, because it describes the motion of the body completely.
Types of velocity:
1. Regular Velocity
2. Irregular Velocity
Regular Velocity: It is Regular Velocity: It is the
the velocity that a body velocity that a body travels in equal
travels in equal displacements displacements and equal time
and equal times (constant velocity of magmitude and
and equal times (constant velocity of magmitude and
(constant velocity of direction)
magnitude and direction)
magnitude and direction)
1. Instantaneous velocity
2. Average velocity
Average Velocity: is Instantaneous Velocity:
a displacement is velocity of a body at a given
from start point to moment Mathematical equation:
end point divided It is determined from the slope of
by total time a tangent to a [displacement and
mathematical equation: time] curve at a specific point
by total time a tangent to a [displacement and
mathematical equation: time] curve at a specific point
v=Total displacement/total time
*instantaneous velocity and average velocity equalized when the body moves by irregular Velocity
*You can calculate the displacement that the body cuts from the [velocity and time] curve (the area under the curve)
*You can calculate the displacement that the body cuts from the [velocity and time] curve (the area under the curve)
if the moving body's velocity changes from point to another whether it is a magnitude, a direction, or both with respect to time, that is called Acceleration.
mathematical equation:
a=Δv/Δt
a= (v2-v1)/(t2-t1)
Types of acceleration:
1. Regular Acceleration
2. Irregular Acceleration
Irregular acceleration: is Regular acceleration: is the
the acceleration that acceleration that a body
a body travels in unequal travels in equal velocity
velocity and equal times and equal times
a body travels in unequal travels in equal velocity
velocity and equal times and equal times
If we consider the direction of the body's velocity to be the positive direction, find that the body is moving with :
1. Acceleration (increasing velocity over time)
2. Ceceleration (decreasing velocity over time)
3. Zero acceleration (constant velocity over time)
.png){kind=link}
.png){kind=link}
.png){kind=link}
.png){kind=link}
.png){kind=link}
.png){kind=link}
.png){kind=link}
.png){kind=link}
*when body moves in straight line and with regular acceleration, we can calculate the average velocity from this equation:
*If the body starts moving from rest, then its initial velocity = 0
If the body stops moving (like If the driver presses the brakes until the car stops), then its final velocity = 0
when the initial velocity is bigger than final velocity, then the body moves with acceleration (increasing velocity)
when the final velocity is bigger than initial velocity, then the body moves with deceleration (decreasing velocity)
when the initial velocity equals than final velocity, then the acceleration = 0 (regular velocity)
If the body stops moving (like If the driver presses the brakes until the car stops), then its final velocity = 0
when the initial velocity is bigger than final velocity, then the body moves with acceleration (increasing velocity)
when the final velocity is bigger than initial velocity, then the body moves with deceleration (decreasing velocity)
when the initial velocity equals than final velocity, then the acceleration = 0 (regular velocity)