Answer:
3 km/h
Explanation:
Let's call the rowing speed in still water x, in km/h.
Rowing speed in upstream is: x - 2 km/h
Rowing speed in downstream is: x + 2 km/h
It took a crew 9 h 36 min ( = 9 3/5 = 48/5) to row 8 km upstream and back again. Therefore:
8/(x - 2) + 8/(x + 2) = 48/5 (notice that: time = distance/speed)
Multiplying by x² - 2², which is equivalent to (x-2)*(x+2)
8*(x+2) + 8*(x-2) = (48/5)*(x² - 4)
Dividing by 8
(x+2) + (x-2) = (6/5)*(x² - 4)
2*x = (6/5)*x² - 24/5
0 = (6/5)*x² - 2*x - 24/5
Using quadratic formula
A negative result has no sense, therefore the rowing speed in still water was 3 km/h
The one that research has determined about the orbit of an electron around nucleus is : Each sub-level electron type has a unique path where it will likely to be found
Here are the sub levels of an electron :
-sub level s, maximum number of 2 electrons
- sub level p, maximum number of 6 electrons
- sub level d, maximum number of 10 electrons
- sub level f, maximum number of 14 electrons
Answer:
Hey mate....
Explanation:
This is ur answer....
<h3><em>The International System of Units (SI), commonly known as the metric system, is the international standard for measurement.</em></h3>
Hope it helps!
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Answer:
(B) tightly packed protons and neutrons
Explanation:
- Nucleus of any atom is the dense central part of any atom.
- It consists of two sub-atomic particle namely proton and neutron.
- These sub-atomic parts are tightly packed in nucleus which makes the nucleus dense .
- This dense nucleus is responsible for most of the mass of atom.
- The atomic mass for any atom is decided by sum of the mass of proton and neutron
Thus, correct answer is
(B) tightly packed protons and neutrons
The force of gravity on a certain object is calculated through the equation,
F = Gm1m2 / r²
where F is the force, G is a constant, m1 and m2 are masses of the object and Earth, respectively and r is the distance. Substituting the known values for this item,
F = (6.67 x 10⁻¹¹ N.m²/kg²)(1 kg)(5.98 x 10²⁴ kg)/ (6.4 x 10⁶ m)²
F = 9.37 N
Answer: 9.37 N
