1. Center of Mass

5. Definition
Point which moves as if all the mass of a system is concentrated there.

6. Motion of Center of Mass
All of the kinematics equations describe the motion of the center of mass of a particle

7. System of Point Masses

8. Example
(3m,3m)
(0,3m)
2 kg
3 kg
(3m,0)
4 kg

9. Projectile example 30 m/s 60° t = 4s (57.3m,28.2m) 2 kg (64.1m,26.8m)
BOOM
2 kg
(64.1m,26.8m)
3 kg
(58.7m,23.6m)
30 m/s
5 kg
60°

10. Center of mass

11. Projectile X Y x= y= xo=0 yo=0 vx=30cos60 vy= vxo=30cos60 vyo=30sin60
ax =0
ay = -9.8
t = 4

12. Projectile Equations