What is apparent magnitude and what can affect it?

Apparent magnitude means how bright a star APPEARS to us on Earth. It can be affected by ...

... how bright the star really is
... how far the star is from us
... how much gas and dust is between us
... how much of the star's total output is in visible light

Speed of 3 m per second means that in one second he ran 3 m, so every second he runs another 3 m.
1 sec. 3m
2 sec. 3+3 or 3•2= 6m
.
45 sec 3•45= 135m