In this case, since the radioactive decay is considered as first-order kinetic model, whereby the remaining mass of the radioactive material involves the initial one, the rate constant and elapsed time:

$A=Ao*exp(-kt)$

As we were not initially given the rate constant, we can use the half-life to calculate it as follows:

$k=\frac{ln(2)}{8.040days}=0.08621days^{-1}$

Thus, we can calculated the elapsed time for the given conditions to obtain:

$t=\frac{ln(0.75g/40.0g)}{-0.08621days^{-1} }\\\\t=46.13days$

Regards!

6 0

3 years ago

a muscle fiber contracts when myosin filaments pull actin filaments closer together and thus shorten sarcomeres within a fiber.

kakasveta [241]

Answer:According to the sliding filament theory, a muscle fiber contracts when myosin filaments pull actin filaments closer together and thus shorten sarcomeres within a fiber.

Explanation:

No need for an explanation if i just answered it

7 0

2 years ago