50. Dynamic Track Collisions

Elastic and inelastic collisions between carts can be demonstrated as one end of the carts are equipped with magnets and the other end with Velcro. A moving cart collides elastically with a stationary cart of equal mass using the magnetic ends. The originally stationary cart moves away with all the velocity. Elastic collisions between carts of different masses can be tried qualitatively or quantitatively with Data Studio.

Completely inelastic collisions result by colliding the Velcro ends of the carts. A carts velocity is measured before and after it has collided inelastically with another cart of equal mass. It is demonstrated that the velocity of the two carts after the collision is half the initial value.

Elastic Collision

Inelastic Collision

Explosions are demonstrated by touching the ends of two carts together and releasing an internal plunger from one of the carts.

Explosion

 

All of the above demos may also be demonstrated with the air track at the instructor's request. The air track has an advantage over the dynamics track in that there is less friction associated with it. However, the air track has a draw-back in that it is much nosier than the dynamics track and in a lecture setting it is difficult for the instructor to be heard.