GeoGebra Classroom

# Multiple Ejections Versus Rocket Equation

## Instructions

This simulation shows the velocity of a projectile (in blue) after ejecting some portion of its mass. The number of pieces to divide the ejected mass into can be selected, as can the fraction of the total mass that is ejected. As more pieces are ejected, the speed of the projectile approaches the value given by the rocket equation (shown in red). The play icon in the bottom left corner can be used to animate the scene. The scene will run in reverse (showing one or more collisions) when the projectile reaches the edge of the screen. In all cases, the ejected boxes are launched at a speed of 1 m/s relative to the blue projectile.
1. Do you end up with a larger final velocity for the projectile if you eject the mass all at once, or if you break the mass into many pieces?
2. If several boxes are ejected, which has the greatest velocity to the left: the first or the last to be ejected? Why is there a difference?
3. Is it possible for an ejected box to end up moving to the right?
4. How does the graph change as the amount of mass ejected changes?