# Half-life

Level pending

A half-life is the amount of time required for a quantity to fall to half its value as measured at the beginning of the time period. Suppose that a radioactive element has $$10$$ seconds of half-life. If this element moves with a constant velocity of $$260,000$$ km/s for $$20$$ seconds, as measured by an observer at a fixed spot, how much of it is left compared to the initial amount? (Assume that the velocity of light is $$300,000$$ km/s and $$\frac{26^2}{30^2}=0.75.$$)

×

Problem Loading...

Note Loading...

Set Loading...