Jai was measuring the radioactivity of different radioactive isotopes. isotope a had a starting radioactive level of 50 g, and after 4 days it measured at 30 g. isotope b had a starting radioactive level of 75 g, and after 4 days it measured at 25 g. which best explains the isotopes?
a.)isotope a has a shorter half-life than isotope b.
b.)isotope a has a longer half-life than isotope b.
c.)isotope a has half the half-life of isotope b.
d.)isotope a has twice the half-life of isotope b.

Plss anybody know how to do this? ? i need the answers from a through d

If steel is more dense that lake water, why can a boat float

Very large accelerations can injure the body, especially if they last for a considerable length of time. one model used to gauge the likelihood of injury is the severity index ( ), defined as =/ . in the expression, is the duration of the accleration, but is not equal to the acceleration. rather, is a dimensionless constant that = the number of multiples of that the acceleration is equal to.in one set of studies of rear-end collisions, a person's velocity increases by 13.7 km/h with an acceleration of 36.0 m/s2 . let the + direction point in the direction the car is traveling. what is the severity index for the collision?