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3 years ago

Help meee please fill in the blanks !!

Physics

1 answer:

Ratling [72]3 years ago

3 0

The atomic number is the simply the number of protons in the atom. So in the first row with atomic number 2, the number of protons is 2.

If the atom has no charge, which I think you can assume for all of these, the number of electrons is equal to the number of protons. So the number of electrons is also 2.

The number of neutrons (which are the particles with no charge in the nucleus) is simply the mass number minus the atomic number i.e. 4 - 2 = 2.

The isotopic symbol is the symbol which is found on the periodic table of elements. There are 2 numbers associated which each element on the table. The larger is the mass number and the smaller is the atomic number. The atomic number or number of protons is what identifies the element. Looking at the periodic table ( https://sciencenotes.org/wp-content/uploads/2015/01/PeriodicTableOfTheElementsBW.pdf or https://simple.wikipedia.org/wiki/Periodic_table_(big) ), it can be seen that the element on the first row above with an atomic number of 2 is Helium with a symbol He. The number that is included with the name is simply the mass number which is 4 in this case, which tells us that this type of helium has 2 neutrons.

Another type (or isotope) of helium is Helium-3 which has one neutron.

Try the next row and post back if you have trouble with it

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The 8 kg block is then released and accelerates to the right, toward the 2 kg block. The surface is rough and the coefficient of

natita [175]

Answer:

3.258 m/s

Explanation:

k = Spring constant = 263 N/m (Assumed, as it is not given)

x = Displacement of spring = 0.7 m (Assumed, as it is not given)

$\mu$ = Coefficient of friction = 0.4

Energy stored in spring is given by

$U=\dfrac{1}{2}kx^2\\\Rightarrow U=\dfrac{1}{2}\times 263\times 0.7^2\\\Rightarrow U=64.435\ J$

As the energy in the system is conserved we have

$\dfrac{1}{2}mv^2=U-\mu mgx\\\Rightarrow v=\sqrt{2\dfrac{U-\mu mgx}{m}}\\\Rightarrow v=\sqrt{2\dfrac{64.435-0.4\times 8\times 9.81\times 0.7}{8}}\\\Rightarrow v=3.258\ m/s$

The speed of the 8 kg block just before collision is 3.258 m/s

7 0

3 years ago

two forces P and Q pass through a point A which is 4 ft to the right of and 3 ft above a moment center O. force P is 200 lb dire

valentinak56 [21]

Thank you for posting your question here at brainly. I hope the answer will help you. Feel free to ask more questions here.

The moment of the resultant of these two forces with respect to O 376 lb-ft CCW which is <span>about moment center point O.</span>

6 0

2 years ago

An elevator and its load have a combined mass of 1650 kg. Find the tension in the supporting cable when the elevator, originally

gizmo_the_mogwai [7]

Answer:

Tension in the supporting cable is = 4,866 N ≅4.9 KN

Explanation:

First of all, we need to understand that tension is a force, so the motion law

F = Ma applies perfectly.

From Newtons third law of motion, action and reaction are equal and opposite. This means that the force experienced by the elevator, is equal to the tension experienced by the spring.

Parameters given:

Mass of load = 1650 kg

Acceleration of load = ?

The acceleration of the load can be obtained by diving the change in velocity by the time taken. But we need to know the time taken for the motion to 41 m.

Time taken = distance covered / velocity

= $\frac{41m}{11m/s}$ = 3.73 seconds

∴Acceleration = ( initial velocity - final velocity )/ time taken

Note: Final velocity is = 0 since the body came to a rest.

Acceleration = $\frac{11 - 0 m/s}{3.73s}$ = 2.95m/ $s^{2}$

Force acting on the cable = mass of elevator × acceleration of elevator

= 1650 × 2.95 = 4869.5 kg ≅ 4.9 KN

6 0

3 years ago

When energy is converted from one form to another in a chemical or physical change, which of the following also changes by a mea

ArbitrLikvidat [17]

Answer:

None of the above

Explanation:

When energy is converted from one form to another in a chemical or physical change, none will change. This is due to the law of conservation of energy. It states that the total energy of the system remains constant. It only changes energy from one form of energy to another. So, the correct option is (d) "none of the above".

3 0

2 years ago

What property of water allows it to rise up in a plant

Alex

Transpiration is the evaporation of water through leaf stomata. It is the major force moving water through plants. Cohesion and adhesion create tension within xylem that helps move water upward.

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3 years ago