Radioactive isotopes are used to a. determine the absolute age of rocks. c. determine how rocks are formed. b. determine the relative age of rocks. d. determine how rocks are changed. select the best answer from the choices provided a b c d

a. determine the absolute age of rocks.

Explanation: Radioactive isotopes being unstable decay by emitting particles and the rate of disintegration at any time depends on the number of atoms of the radioactive isotope present at that time.

Hence radioactive decay follows first order kinetics.Thus, if atoms of radioactive isotope are present initially and N atoms are present after time t, then

Rate of disintegration at time t

where k= disintegration constant

The expression used to calculate the absolute age is:

where,

k = rate constant

t = time taken for decay process

a = initial amount of the reactant

a - x = amount left after decay process

russian is not my first language, so i'm afraid i can't write out an answer in russian, but hopefully you can find a way to do so. here's my best translation of the problem: you're given a plot of a particle's position in one-dimensional space over time, and you're asked to find either the total distance traveled by the particle after 6 seconds had elapsed, or the total displacement of the particle after 6 seconds.

if you want the total distance traveled, you would first need to determine the particle's velocity as a function of time, then integrate that over the 6-second interval. we know the position function is quadratic with roots at 0 and 6, so we have

where is unknown. because the position is parabolic, there is symmetry about the midpoint at , and we know that

so that the position function is

which means the velocity is

then the total distance traveled is

so the total distance traveled is 20 m.

on the other hand, if you want to find displacement: the particle starts at and ends at , so its displacement is 0.