2D and 3d motion analysis
Mazarik university
BMX trick
lenght of the skate :
I calibrated the system of pixel putting the coordinates of two
points (upper and lower points of the skate) in the calibration
section of excel.
-on the video : 1,53cm
-real lenght : 60cm
60/1,53=39,21
=>so each distance must be multipicate by 39,21 to become true
Lenght of the jump :
1st
picture :
distance from the skate : 3,94cm
real distance : 3,94*39,21= 154,5cm
2nd
picture :
distance from the skate : 2,04cm
real distance : 80cm
Total lenght of the jump :
154,5+80= 234,5cm
=>2,345 metres
Speed
Time in the air :
I toke the time written on the video at the beginning of the jump
and then at the end.
Time at the first frame of the jump : 2,20 sec
Time at the last frame of the jump :3,00 sec
Total time in the air :
3,00-2,20=0,80 sec
Speed in the air :
2,345/0,80=2,93
2,93 m/s
and 10,55 km/h
Height
high of the jump : 1,83cm
real high : 71,75cm
Angle of the jump
A= the highest point of the jump
B= the beginning of the jump
We need the angle B
Tan(B)=71,75/154,5
so Tan(B)=0,464
so B = 24.89°
71,75cm
154,5c
m
A
BC