| Collisions per Second Meter: This meter measures the rate at which cannon balls collide with the wall. You must attach the collision rate meter to a red hotspot on the wall (see Cannons & Wall). Only the probe connects to the hotspot on the wall. The meter itself appears to the right. You can move the meter, but you cannot delete it. To delete the meter, you must delete the probe. The product between the displays of this meter and the average impulse meter should approximately equal the total force. You must place a collision rate meter to plot collisions per second using the graph tool.