Answer:
8923 years
Step-by-step explanation:
Half life of C-14 = 5730yrs
decay rate= 34%
Halt life (t^1/2) = (ln2) / k
5730 = (ln2) /k
k = (ln2) / 5730
k = 1.209 * 10^-4
For first order reaction in radioactivity,
ln(initial amount) = -kt
ln(34/100) = -(1.209*10^-4)t
-1.0788 = -(1.209*10^-4)t
t = -1.7088/ -1.209*10^-4
t = 8923 years
Complete question is;
A 21 ft ladder is leaning against a tall wall with the foot of the ladder placed at 7 feet from the base of the wall and the angle of elevation is?
Answer:
θ = 70.5°
Step-by-step explanation:
The angle of elevation simply means the angle that the ladder makes with the ground. Let's call this angle θ.
I've attached a diagram showing the triangle made by this ladder and the wall.
From the attached diagram, we can see the triangle formed by the ladder and the wall.
We can find the angle of elevation θ from trigonometric ratios.
Thus;
7/21 = cos θ
cos θ = 0.3333
θ = cos^(-1) 0.3333
θ = 70.5°
Each team needs two people for a 3-legged race.
Therefore, the number of orders (combinations) of 2 people at a time from 8 is
₈C₂ = 8!/(2!6!)
= (8*7*6!)/(2*6!)
= (8*7)/2
= 56/2
= 28
Answer: 28
Answer:
srry i need more points
Step-by-step explanation:
<h2>ok dont mean to bother u</h2>
Answer:
39 X 10=75
Step-by-step explanation:
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