The half-life for an 80-gram sample of an unknown radioactive element is 5 days. how much of the unknown radioactive element remains after 10 days have passed? A.20g
B.40g
C70g
d80g

answer: 0

explanation: im   14

causes

fossil fuels burn

cities become more industrialized

human population grows worldwide

pythagoras' theorem

square root (-5^2+9^2)

square root (25+81)

square root (106)

angle is tan^-1(9/5)

neg x, pos y

the aurora is formed when charged particles emitted from the sun during a solar flare penetrate the earth's magnetic shield and collide with atoms and molecules in our atmosphere. these collisions result in countless little bursts of light, called photons, which make up the aurora.

auroras are generated by charged solar particles hitting molecules in earth's atmosphere. this usually happens in high latitudes, because our planet’s magnetic field tends to funnel these particles toward the poles. that’s why it can be experienced in northern ohio.