a1 kinematics

Kinematics

the branch of mechanics concerned with the motion of objects without reference to the forces which cause the motion.

distance

It is the actual length of the path traversed between initial and final positions. Scalar, can never be negative for a moving body.

displacement (define)

It is the length of the shortest path.between initial and final positions. Vector, can be negative for a moving body.

vector quantity

magnitude (size) and a spatial direction: Velocity, displacement, force, weight and acceleration

scalar quantity

only magnitude (size): Speed, distance, time

Instantaneous velocity

the velocity of a moving object at one specific moment.

Average velocity

velocity measured over a certain time interval.

constant velocity

Instantaneous velocity = Average velocity

Acceleration

the change in velocity over time / Rate of change of velocity

Equations of motion for uniform acceleration 

displacement = (initial velocity)(time) + ½ (acceleration)(time)²

final velocity = initial velocity + (acceleration)(time)

(final velocity)² = (initial velocity)² + 2(acceleration)(displacement)

displacement = ½ (initial + final velocity) x time

area under velocity-time graph

displacement

area under an acceleration-time graph

change in velocity

types of projectile

θ = 0 (horizontal projectile)

θ = 90 (vertical projectile)

θ = θ

horizontal projectile, find range

x = ut

horizontal projectile, find height

H = ½ gt²

non-horizontal projectile, find x and y component of velocity

u_x= ucosθ

u_y=usinθ

non-horizontal projectile, find range

x = ucosθt

non-horizontal projectile, find height

y = usinθt + ½ gt²