Question

A 39 gram sample of a substance that's a by-product of fireworks has a k-value of 0.1024.

N = N0e -kt

N0 = initial mass (at time t = 0)

N = mass at time t

k = a positive constant that depends on the substance itself and on the units used to measure time

t = time, in days


Find the substance's half-life, in days.

Round your answer to the nearest tenth.

Answer 1

please help

Answer 2

@puppylover52

Answer 3

srry idk this one

Answer 4

the equation is
\[\frac{N(t)}{N_o} = e^{-kt}\]
set N /No to 1/2 and that is what half life means, the time for the amount to halve
\[\frac{1}{2} = e^{-0.1024T}\]

take logs and solve for T, where t = T is the half life

Answer 5

nice work @IrishBoy123 !

Answer 6

so the answer cause I cant solve it?

Answer 7

@IrishBoy123 @Jack1

Answer 8

i solved for t and its still not it

Answer 9

i think u use t to solve the 1/2 life... yeah?

Answer 10

no, in irish's example: t is the half life

Answer 11

can you find the answer @Jack1 ?

Answer 12

yeah, i have the answer, what did u get for t?

Answer 13

like 6.790

Answer 14

yep, same here, exact answer for half life is t=6.76902 ish

Answer 15

all i have is grams tho, i don't know the units of k, so i have no idea of the units of t or if k and t are both in the same units of measure...?

Answer 16

(eg if k's relates to pounds/second or something and our No is in grams we have a problem)

Answer 17

so you think you can solve it?

Answer 18

@IrishBoy123

Answer 19

lol... wat? so 6.8 isnt ur answer? (rounded to the nearest tenth)

Answer 20

lol it is now my computer got messed up so it was saying everything incorrect thanks @Jack1

Answer 21

ha. s'cool ;)