Present. NOT SURE IF THIS IS EVEN RIGHT!! I JUST GUESSED AND THOUGHT
Answer:
0.027648 kgm²
Explanation:
M = Mass of disc = 1.2 kg
r = Radius of disc = 0.16 m
m = Mass of rod = 0.16 kg
R = Rod distance = 0.16 m
Moment of inertia of disk is given by
Moment of inertia of the three rods
The total moment of inertia is given by
The moment of inertia of the stool with respect to an axis that is perpendicular to the plane of the disk at its center is 0.027648 kgm²
If the two waves have the SAME FREQUENCY and are exactly
out of phase (180° apart), then the resultant wave will have the
same frequency and an amplitude of 1 unit.
If the two waves do not have the SAME FREQUENCY, then their
relative phase is meaningless.
The answer should be C. In this question
<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
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