MOTION ALONG A STRAIGHT LINE | 1.1

Mechanics

The branch of physics involving the motion of an object and the

relationship between that motion and other physics concepts.

kinematics / dynamics

two branches of mechanics

Kinematics

deals with the description of motion.

- 1D motion - Projectile motion

- Circular motion - Relative Motion

Dynamics

deals with causes of motion.

- Newton’s Laws of Motion

- Momentum and Energy

One-dimensional (1D) Motion

considering objects to travel along a flat and narrow straight

line (rectilinear motion)

object is considered as point particle

One-dimensional (1D) Motion

considering objects to travel along a flat and narrow straight

line (rectilinear motion)

object is considered as ______

Reference Frame

a physical entity to which the motion and position

of objects are referred.

Distance

➢ scalar quantity

➢total length traveled

➢ denoted by s

distance formula

Displacement

➢ vector quantity

➢shortest distance from initial to final position

➢ change in position denoted by Δx or Δy

displacement formula

Speed (Average Speed)

➢ scalar quantity

➢ “how fast the object is moving?”

Speed (Average Speed) formula

Velocity (Average Velocity)

➢ vector quantity

➢ “the rate at which an object changes its position”

➢ denoted by v

Velocity (Average Velocity) formula

Average Speed

➢Total distance traveled,

regardless of direction

➢Cannot have a negative

average speed

Average Velocity

➢Needs info on origin

and positive x-axis

➢Displacement is

important, NOT

distance.

➢Can have a negative

average velocity

average speed formula

average velocity

Slow

rightward (+x)

Fast

rightward (+x)

Fast

leftward (-x)

Slow

leftward (-x)

Instantaneous velocity

defined as

the limit of the average velocity as the

time interval becomes infinitesimally

short, or as the time interval

approaches zero

Instantaneous velocity formula

Acceleration

The magnitude of the velocity is changing whether

increasing or decreasing.

✓ The magnitude of the velocity is constant but the there

is a change in direction.

✓ Change in velocity magnitude and direction.

Acceleration

➢ vector quantity

➢ “The rate at which the object changes it velocity.”

➢ denoted by a

Uniformly Accelerated Rectilinear Motion (UARM)

➢UARM means motion in straight with constant acceleration

(g= -9.8 m/s^2)

acceleration due to gravity value