240 = 0+1/2 (-9.8t
240 = -4.9t
<span>240/-4.9 = t</span><span>
</span>49.0 = t
t= 7.0s
4 Hz is the difference between 510 and the unknown.
<span>Therefore the unknown is either 514 or 506. </span>
<span>If 505 and 506 were struck together, the diff would be 1 Hz </span>
<span>If 505 and 514 were struck toghether, the diff would be 9 Hz which would be difficult to count accurately, </span>
<span>Therefore the unknown is 514</span>
As long as green Barghouti on painted charge. (Answer matches logic of the question.)