Answer:
B.
Step-by-step explanation:
Let n be the number.
We are asked to write an mathematical expression for the given word phrase.
One third of a number, n, would be .
Two more than one third of a number, n, would be .
We are told that Two more than one-third of a number is 8. We can represent this information in an equation as:
Therefore, option B is the correct choice.
Answer:
distance: 320.624 miles
direction: 43.576°
Step-by-step explanation:
The speed and direction can be found by adding the given vectors.
... 320∠40° + 20∠130°
... = (320·cos(40°), 320·sin(40°)) + (20·cos(130°), 20·sin(130°))
... = (245.134, 205.692) +(-12.856, 15.321) = (232.278, 221.013)
The magnitude of the vector with these components is found using the Pythagorean theorem. The direction is found using the arctangent function.
... = √(232.278² +221.013²)∠arctan(221.013/232.278)
... = 320.624∠43.576°
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A suitable vector or graphing calculator can do this easily. In the screenshot of a TI-84 app below, the variable D has the value π/180. The display mode is set to degrees.
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<em>Comment on coordinate systems</em>
Navigation directions are generally measured clockwise from North. Angles in the usual x-y coordinate plane are measured counterclockwise from +x (effectively, East). You can consider the geometry of the navigation coordinate system to be a reflection across the line y=x of the geometry of the usual x-y coordinate system.
Reflection does not change lengths or angles within a given geometry. Hence, we can use all the usual tools of vector calculation using navigation coordinates, without bothering to translate them back and forth to x-y coordinates.
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Problems like this generally can be worked using the Law of Cosines and the Law of Sines, too. It generally helps to draw a diagram so you can find the values of the angles betwee the various vectors more easily.
Correct question:
Which reaction describes a beta emission? 2659Fe→ 2759Co + −10e, 88226Ra→ 86222Rn + 24He, 94239Pu + 24He→ 96242Cm + 01n, 54118Xe→ 53118I + +10e
Answer:
2659Fe→ 2759Co + 1e
Step-by-step explanation:
General equation for beta decay is given as;
where;
A is the atomic mass of the element
z is atomic number of the element
X is the parent atom
Y is the daughter element
β is beta emission
In beta emission, there is loss of one electron and zero proton, the will cause the daughter element to gain on electron in order to balance the reaction.
Based on beta decay equation above, we select the reaction that describes beta emission.
2659Fe→ 2759Co + 1e
Here;
A = 59
z = 26
z + 1 = 27