4 - Kinematics

Mechanics

a branch of physics that focuses with the motion of objects and the forces that cause that motion to change

• Kinematics

• Dynamics

Parts of Mechanics: (2)

Kinematics

deals with the concepts that are needed to describe motion, without any reference to forces

Dynamics

deals with the effect that forces have on motion

Motion

the action or process of moving or of changing place or position

Distance

Define the length of the path travelled.

Distance

Considered a scalar property, meaning it refers only to the total magnitude and does not account for start or endpoints.

Displacement

Define the length and direction from start to finish.

Displacement

This accounts for the magnitude as well as the direction of an object's travel, making it a vector quantity.

Distance

is represented by the letter d

Displacement

is represented by the letter s

Displacement

defined as the total change in the object’s position along with the direction of motion.

Distance

can only have positive values.

Displacement

can be positive, negative, or zero.

• Speed

• Velocity

• Acceleration

PHYSICAL QUANTITIES That Described Motion: (3)

Speed

This the distance traveled per unit of time and describes how fast an object is moving.

speed (s) = d / t

Formula of speed:

Velocity

This is the total distance over which an object travels during a particular interval of time.

v = Xf - Xo (displacement) / t

Velocity formula:

Acceleration

A vector that is defined as the rate at which an object changes its velocity

velocity

An object is accelerating if it is changing its _____

a = Vf - Vo / t

• change in velocity / time

Acceleration formula:

• Identify What You Know

• Identify The Goal

• Gather Your Tools

• Put It All Together

HOW TO APPROACH A KINEMATICS PROBLEM? (4)

• Linear

• Rectilinear

• Curvilinear

• Rotary

• Oscillatory

Types of Motion: (5)

Linear motion

the particles move from one point to another in either a straight line or a curved path.

Rectilinear motion

The path of the motion is a straight line

Curvilinear motion

The path of the motion is curved.

Rotary motion

motion that occurs when a body rotates on its own axis.

Oscillatory motion

the motion of a body about its mean position.

Free Fall

state of a body that moves freely in any manner in the presence of gravity

wind & air resistance

For an object to qualify as being in free fall, factors like ____&____ must be disregarded.

9.81 m/s² (32ft/s²)

On Earth, all objects in free fall accelerate downward at a rate of _____

Projectile Motion

A type of motion in which the object is solely influenced by the force of gravity, with no other forces acting on it.

Projectile Motion

Always follow a curved trajectory.

Trajectory

The curved or parabolic path followed by a projectile.

Range

The horizontal distance of a projectile.

• Horizontal

• Vertical

• Parabolic

Types of Projectile Motion: (3)

Horizontal

Motion of an object rolling freely along a level surface

constant

Horizontal velocity is ALWAYS ______

Vertical

Motion of a freely falling object.

• Force due to gravity

time

Vertical component of velocity changes with ___

Parabolic

Path traced by an object

• accelerating only in the vertical direction

• while moving at constant horizontal velocity

Horizontal component

describes the influence of the velocity in displacing the projectile horizontally and does not depend on its vertical component.

Vertical component

influenced by gravity, which acts vertically on the object causing it to accelerate downward