Answer:
Explanation:
Let A₀ = the original amount of ⁵⁵Co
.
The amount remaining after one half-life is ½A₀.
After two half-lives, the amount remaining is ½ ×½A₀ = (½)²A₀.
After three half-lives, the amount remaining is ½ ×(½)²A₀ = (½)³A₀.
The general formula for the amount remaining is:
A =A₀(½)ⁿ
where n is the number of half-lives
n = t/t_½
Data:
A = 1.90 ng
t = 45 h
t_½ = 18.0 h
Calculation:
(a) Calculate n
n = 45/18.0 = 2.5
(b) Calculate A
1.90 = A₀ × (½)^2.5
1.90 = A₀ × 0.178
A₀ = 1.90/0.178 = 10.7 ng
The original mass of ⁵⁵Co was .
Independent variable: calculators, computers
Dependent variable: speed
3 constants: seat, atmospheric condition, and time.
Control: none
<h3>What are variables</h3>
Variables are of different types in experiments. They can be:
- Independent: a variable that is supplied by the researcher and which can be tweaked among different experimental groups to produce different outcomes.
- Dependent: variables whose value is dependent on the kind of independent variable supplied by the researcher. It is the actual variable that is measured during the course of experiments.
- Constant: all other variables that are kept the same among experimental groups.
Thus, in this case, the independent variable will be the calculator or computer/calculator combination given to the two groups.
The dependent variable will be the speed at which each group finished solving the math problems.
The constant variable will be all other variables supplied to the two groups.
More on variables can be found here: brainly.com/question/20725701
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Answer:
Because they are smaller than an atom
Explanation:
