Answer:i One way to solve the quadratic equation x2 = 9 is to subtract 9 from both sides to get one side equal to 0: x2 – 9 = 0. The expression on the left can be factored:
Explanation:
Answer:
1470kgm/s
Explanation:
Given parameters:
Mass of the rock = 50kg
Time taken for the free fall = 3s
Unknown:
Change in momentum = ?
Solution:
The change in momentum will be difference between the ending momentum and finishing momentum.
Momentum is the product of mass and velocity
Momentum = mass x velocity
Initial momentum = 0, the velocity is 0
Final momentum = mass x final velocity
let us find the final velocity;
V = U + gt
V is the final velocity
U is the initial velocity
g is the acceleration due to gravity = 9.8m/s²
t is the time
V = 0 + 9.8x3 = 29.4m/s
So;
Change in momentum = 50 x 29,4 = 1470kgm/s
<span>In order to calculate an average, we should sum all numbers and divide them by quantity.
Let’s work with qualifications first. Let’s say you got a 10 in 1 exam, then an 8 in 2 exams and a 4 in 2 exams. Your average will be:
= (10*1+8*2+4*2) / 5 = 6.8
If 6 is the minimum, you will pass.
There is another way to calculate this average: applying distributive property.
= 10*1/5+8*2/5+4*2/5 = 6.8
Remember you can convert the fractions into equivalent fractions: 1/5 = 20/100; 2/5 = 40/100
= 10*20/100+8*20/100+4*20/100 = 6.8
We actually don’t have the number of atoms of each mass… we have the percentage instead! So we need to learn this last method for atoms.
Let’s go back to our atoms problem:
73.71 % of atoms have a mass of 27.98 u
14.93 % of atoms have a mass of 28.98 u
11.36 % of atoms have a mass of 29.97 u
So let’s put that in the formula:
Average mass = 27.98 u*73.71 /100 + 28.98 u*14.93 /100 + 29.97u*11.36 /100
So what you have to know is that a percentage can be converted into a fraction, and you should work that fraction in order to find the average. We can make the calculus shorter putting 100 as the common denominator:
Average mass = (27.98 u*73.71 + 28.98 u*14.93 + 29.97u*11.36)/100
So actually we are taking the percentage as if it was the quantity, and 100 as if it was the total (the total of all percentages is always 100). Maybe we don’t have 100 atoms, but it will be the same proportion anyway, whatever number we have! And here it is the result:
Average mass = 28,36u
</span>
Answer:
<em>C. It is made from three layers of semiconductors.</em>
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Explanation:
<em>Bipolar transistors (pnp and npn) are usually made from a sandwich of three semiconductors layers</em>. The main charge carriers are holes and electrons. An npn transistor has two semiconductor junctions that share a thin middle positively enhanced region (the material is enhanced with impurities rich in holes which are the positive charge carriers), and a pnp transistor has two semiconductor junctions that share a thin middle negatively enhanced region (material is enhanced with impurities rich in electrons, the negative charge carriers).
