I NEED HELP I DOMT KNOW HOW TO DO THIS

7. The timing of a 100-meter race.

Explanation:

I'm not supposed to add an actual number to this so there isn't rlly an explanation. If you need an example of why my answer is legible, continue reading.

You could say 13.0 seconds as if it were exact, but it is really an approximation subject to significant digit rules. (3 s.f.)

The actual number could have been 13.03. However, due to the fact that perhaps you just wanted to know whether it was below 10 seconds, it does not really matter whether it was 13.03 seconds or just 13.0 seconds.

particle   p is an electron and particle q is a neutron