The mass of cesium left afer 120 years if the original mass of cesium is 8640 with an half-life of 30 years, is 540 grams.
<h3>What is half-life?</h3>
This can be defined as the time taken for half the amount of a radioactive substance to decay.
To calculate the amount of cesium left after 120 years, we use the formua below.
Formula:
- R' = R/(
)............. Equation 1
Where:
- R = Original amount of Cesium
- R' = New amount of cesium
- T = Total time
- t = Half-life
From the question,
Given:
- R = 8640
- T = 120 years
- t = 30 years
Substitute these values into equation 1
- R' = 8640/(
) - R' = 8640/

- R' = 8640/16
- R' = 540 grams.
Hence, The mass of cesium left afer 120 years is 540 grams.
Learn more about half-life here: brainly.com/question/25750315
Answer: 
Step-by-step explanation:
By the negative exponent rule, you have that:

By the exponents properties, you know that:

Therefore, you can rewrite the left side of the equation has following:

Descompose 32 and 8 into its prime factors:

Rewrite:

Then:

As the base are equal, then:

Solve for x:

<span>A chord divides a circle into 2 segments.
A major segment and a minor segment.
If the chord passes through the center of the circle, then it divides the circle into equal segments.</span>
1.6*100/0.95=168% 1.6 to 0.95
0.95*100/1.6=59% 0.95 to 1.6
8/13 = 0.6153
y = cos-1(0.6153)
y = 52.0
I'm not totally sure if this is what you mean or if this is.
y = cos(8/13) = 0.9999 which to the nearest tenth is 1.0