Answer: 20 mg Te-99 remains after 12 hours.
Explanation: N(t) = N(0)*(1/2)^(t/t1/2)
N(t) = (80 mg)*(0.5)^(12/6)
N(t) = 20 mg remains after 12 hours
1- thé everyday use of kinematic basically the speed for something it’s the magnitude.
2-the speed of something in a certain direction
2a- They are both related by speed.
3-the capacity of a vehicle which gains speed in a short time
4-it’s an attraction of all matter (not sure on this one)
