Answer:
Kinetic energy
Explanation:
Objects or particles under motion posses energy in the form of kinetic energy which is directly proportional to the square of the velocity of the given particle.
E= 1/2mv² where m is the mass of the particle and v the velocity of the particle.
The number of years required for 1/4 cobalt-60 to remain after decay is calculated as follows
after one half life 1/2 of the original mass isotope remains
after another half life 1/4 mass of original mass remains
therefore if one half life is 5.3 years then the years required
= 2 x 5.3years = 10.6 years