1-D Kinematics

Describing Motion

• Science of describing motion.• Words• Diagrams• Numbers • Graphs• Equations• Develop sophosticated mental models

that describe the motion of real-world objects.

Kinematics

• System used to describe motion that indicates when the zero point of the variable is located and the direction in which the values of the variable increase.

• Origin: point in which the variable has a value of zero.

• Position vector: arrow used to identify the position of the moving object at any given time.

• Length of the position vector is proportional to the distance of the object from the origin and points of origin to the location of the moving object at a particular time.

Coordinate Sytems

• Quantities that are described by magnitude (numerical value) only.

• Time• Mass• Temperature

Scalars

• Describe magnitude and direction

• Acceleration

• Velocity

Vectors

• Distance: scalar quantity. It is referring to how far an object moves “distance covered”. • d0 to d1

• Displacement: vector quantity. Refers to the distance and direction Δd = d1

– d0

Distance and Displacement

1 1 Distance vs Displacement

• Velocity: speed and direction that an object moves.• Vector quantity• Speed =distance traveled/time of

travel s = d/t• Velocity = Δ position/time = Δd /Δt• Instantaneous speed is speed at any

given point of time.• Average speed – average of all

instantaneous speeds.

Velocity vs Acceleration

• Acceleration: rate at which an object changes it’s velocity.• Vector quantity• Constant Acceleration : when an

accelerating object changes Its velocity by the same amount each second.

• Average acceleration = Δ velocity/time or

a = vf - vi / t