Answer:
The mass of the radioactive sample after 40 minutes is 12.8 g.
Step-by-step explanation:
The mass of the sample can be found by using the exponential decay equation:
Where:
N(t): is the amount of the sample at time t =?
N₀: is the initial quantity of the sample = 120 g
t = 40 min
λ: is the decay constant = 0.056 min⁻¹
Hence, the mass of the sample after 40 min is:
Therefore, the mass of the radioactive sample after 40 minutes is 12.8 g.
I hope it helps you!
Answer:
Step-by-step explanation:
x-7y = -49
i) move x to the right-hand side and change its sign
-7y = -49-x
ii) change the signs on both sides of the equation
7y = 49+x
iii) divide both sides of the equation by 7
iv) use the commutative property to reorder the terms
* commutative property: a+b = b+a
It would take 9 people 34.5 minutes to paint 9 walls.
23 divided by 6 equals 3.83. That is how many minutes it takes one person to paint one wall. Multiply 3.83 by 9 and you get your answer, 34.5 minutes.
Answer:
a). -5.7 meters or 5.7 meters below sea level
b). When we combine the two depths we sum them since they are an increment in the same direction and we sum them from the seal level, our first reference point.
Step-by-step explanation:
a). Final depth=Initial depth+deeper increment=(-1.5)+(-4.2)=-5.7
Initial depth=-1.5 represented by a negative number since she is below sea level, meaning her reference point(point 0) is the sea level. The more she moves below the sea level the deeper she goes and the more her depth becomes negative
Deeper increment=-4.1, she further moves deeper from her initial depth(-1.5) by a value of -4.1. In order to find her final depth, we have to sum all the depths she covered from her first reference point which is the see level.
The expression is;
Final depth=Initial depth+deeper increment=(-1.5)+(-4.2)=-5.7 meters
Her final depth=-5.7 meters
b). When we combine the two depths we sum them since they are an increment in the same direction and we sum them from the seal level, our first reference point.
Okay
1 yes and yes
2 yes and no
3 no and yes
