Example in WebAssign

Question box

<script language="JavaScript">
var ball_1_<EQN $appletname = 'Animator_'.(++$numanim)> = 0;
var ball_2_<EQN $appletname> = 0;
function initialize_<EQN $appletname>(){       
        document.<EQN $appletname>.setShapeRGB(255,0,0);
        ball_1_<EQN $appletname> = document.<EQN $appletname>.addObject("circle", "x=-22+(12*t),y=-2,r=10");
        eq = "-20";
        document.<EQN $appletname>.setShapeRGB(0,0,255);
        ball_2_<EQN $appletname> = document.<EQN $appletname>.addObject("circle", "x="+eq+", y=2,r=10");
        document.<EQN $appletname>.setTimeOneShot(5,"End");
        document.<EQN $appletname>.setTrail(ball_1_<EQN $appletname>,300);
        document.<EQN $appletname>.setFootPrints(ball_1_<EQN $appletname>,20);
        document.<EQN $appletname>.setGhost(ball_1_<EQN $appletname>,true);
        document.<EQN $appletname>.setTrail(ball_2_<EQN $appletname>,300);
        document.<EQN $appletname>.setFootPrints(ball_2_<EQN $appletname>,20);
        document.<EQN $appletname>.setGhost(ball_2_<EQN $appletname>,true);
  

        document.<EQN $appletname>.forward();
}

</script>

<h2>
One dimensional motion with constant velocity.</h2>

<center>
<p><applet code="animator4.Animator.class"
    codebase="<EQN $PHYSLETPATH>" id="<EQN $appletname>" name="<EQN $appletname>"
    archive="Animator4_.jar,DataGraph4_.jar,STools4.jar"
    width="500" height="200">
        <param name="FPS" value="10">
        <param name="dt" value="0.02">
        <param name="pixPerUnit" value="10">
        <param name="gridUnit" value="1.0">
        <param name="showControls" value="false">
</applet>
<br><input type=button value="Run" onClick="Javascript:document.<EQN $appletname>.forward()">
<input type=button value ="Step Forward" onClick="Javascript:document.<EQN $appletname>.stepTimeForward()">
<input type=button value ="Step Backward" onClick="Javascript:document.<EQN $appletname>.stepTimeBack()">
<input type=button value="Pause" onclick=Javascript:document.<EQN $appletname>.pause()>
<input type=button value="Reset" onclick="Javascript:document.<EQN $appletname>.reset()">
</center>
<a href="JavaScript:initialize_<EQN $appletname>()">Click here</a> to start. 
Write the equation of motion as a function of <i>t</i> in the box below.
x = <_>

Answer box

t:-22+(12*t)