## Wednesday, July 11, 2012

### Particles Motion Kinematics

To reach the orbit, an instrument in the flight control room always monitors the position of the shuttle space an calculates velocity and the acceleration from a given position.

1. Position

Position is the location of a particle relative to a frame of reference and expressed by the vector quantity r.
In a Cartesian coordinate, we use unit vector perpendicular to each other :
Unit vector i ( in x direction)  and unit vector j ( in y direction).
If the particle or object is at point (x,y), then is position expressed as
r = xi + yj

r = 5 i+ 5 j

Displacement

2. Displacement is the change in position of partikel expressed as a vector quantity Δr
If r0 is the initial position and rt is the final position, then the displacement can be written mathematically as

r0 + Δr = rt
Δr = rt – r0

Or

Δr = Δxi + Δyj

1. Distance
Distance is the magnitude of displacement traveled by particle a scalar quantity  r| or Δr
Distance can bd write mathematically using Phytagoras theorem.

Δr =

And the direction of the dicplacement θ is

tg θ =

Example

Δr =
Δr =
Δr =
Δr =
Δr =  5

tg θ =  =  = 0, 75

θ = 300

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