second life : LSL : make ball bounce

ball-bounce.lsl

default
{
    on_rez(integer arg) 
    { 
        llResetScript(); 
        
        llSetStatus(STATUS_PHYSICS, TRUE);
        llSetStatus(STATUS_ROTATE_X | STATUS_ROTATE_Y | STATUS_ROTATE_Z, FALSE);        
    } 
          
    state_entry()
    {
//        llSensorRepeat("", NULL_KEY, AGENT_BY_LEGACY_NAME, 10.0, PI, 10);
    }

    touch_start(integer total_number)
    {
        llSay(0, "Touched.");
        llSetStatus(STATUS_PHYSICS, FALSE);
        llSetPos(llGetPos() + <0,0,50>);
        llSetStatus(STATUS_PHYSICS, TRUE);
    }
     
    sensor(integer num_detected)
    {
         float speed = llVecMag(llGetVel());
        llSay(0, "llVecMag="+(string)(speed));
        if (speed < .001 ) {
             llSay(0, "stopped");
            llSetStatus(STATUS_PHYSICS, FALSE);
            llSetPos(llGetPos() + <0,0,50>);
            llSetStatus(STATUS_PHYSICS, TRUE);
        }
    }
    
    collision(integer num_detected) 
    {
        //vector speed = llGetVel();
        //speed.z = speed.z * -1;
        //llSay(0, "collided");
        //llSetVelocity(speed, FALSE);       
        llSetVelocity(<0,0,12>, FALSE);
    }
}