Answer:
5.6 days
Step-by-step explanation:
We are given;
Initial Mass; N_o = 25 g
Mass at time(t); N_t = 25/2 = 12.5 (I divide by 2 because we are dealing with half life)
k = 0.1229
Formula is given as;
N_t = N_o•e^(-kt)
Plugging in the relevant values;
12.5 = 25 × e^(-0.1229t)
e^(-0.1229t) = 12.5/25
e^(-0.1229t) = 0.5
(-0.1229t) = In 0.5
-0.1229t = -0.6931
t = -0.6931/-0.1229
t = 5.6 days
Answer:
r = 2.23
Step-by-step explanation:
Use the formula:
C = 2(pi)r
Solve for r:
r = C
/2π = 14
/2·π = 2.228
