Answer:
452.39
Step-by-step explanation:
to find the surface area of a sphere all you need is the radius (half the diameter) and assuming the sphere touches both top and bottom that makes the radius 6 so your equation is
SA=4πr^2
SA=4*π*6^2
SA=4*π*36
SA=4*113.09
SA=452.389
then rounded up to 452.39, that is your answer
16.15 because 33,60-1.30 is 32.30. 32.30 divided by 2 is 16.15
Half-life, h = 13 hours
Mass initial, a = 38 g
B=base for half-life = 2
(a)
I(t)=a*B^(-t/h)=a*(B^(1/h)^(-t)=a*(B^(-1/13))^t
Substituting values,
I(t)=38*(2^(-1/13))^t
a=38 g
b=2^(-1/13)=0.9480775 (approximately)
=>
I(t)=38*0.9480775^t
(b) I(t)=7
solve
I(t)=7=38*0.948077^t
Take log on both sides and solve for t
t=log(7/38)/log(0.948077)
=31.727 hours.
Check: I(31.727)=38*9.948077^(31.727)=7.000 g ok
Answer:
A) 
Step-by-step explanation:
