If a radioactive sample contained 1600 billion nuclei and its half life was 57 years, after how many years would there be 400 billion nuclei remaining?

hi,

what occurs during a solar eclipse?

there are small tides across earth.

the moon is between earth and the sun.

p.s. im not sure if the first answer is correct because during a solar ecliphse there are spring tides and i dont know if they are the same.

that would be because of both gravity and friction. so     c

a=d/t

a="triangle"v/t

explanation:

a = acceleration