Two steel balls rolling along a grooved track approach each other with different (non-zero) speeds and collide elastically. The speeds are measured with respect to the track. It is possible to adjust the masses of the balls so that

1. both balls stop after collision.

2. one of the balls stops after collision.

3. after collision both balls move in the same direction

4. Several choices are correct.

The script in the header contains the functions called by the button handlers.

Hidden text is used for feedback.

<SCRIPT>
function respond(N){
document.f1.feedback.value=document.f1.elements[N].value
}

function check(N){
c=0;
for(j=0; j<4; j++){
(document.f1.Q1[j].checked==true)?c=j+1:c=c;
}
document.f1.feedback.value="You chose choice #"+c+". The correct choice is #4."
}
</SCRIPT>

Sample button handlers

<INPUT TYPE=radio NAME="Q1" VALUE="q1a" onClick=respond(this.value)>1. both balls stop after collision.

<INPUT TYPE=button NAME="CHECKQ1" VALUE="CHECK MY ANSWER" onClick=check(Q1)>