Write down short notes on:c. Power

1 answer:

4 0

Answer: In the International System of Units, the unit of power is the watt, equal to one joule per second. In older works, power is sometimes called activity. Power is a scalar quantity.

Explanation: SI unit: watt (W)

In SI base units: kg⋅m2⋅s−3

Derivations from other quantities: P = E/t; P = F...

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A 78.5-kg man is standing on a frictionless ice surface when he throws a 2.40-kg book horizontally at a speed of 11.3 m/s. With

kirill [66]

Answer:

The man moves across the ice with a speed of 0.345m/s.

Explanation:

From the conservation of linear momentum, we have that the total linear momentum before the book throw is equal to the total linear momentum just after it. Since the initial velocity of the system is zero (so the initial momentum is zero), we have that:

$m_mv_m+m_bv_b=0\\\\v_m=-\frac{m_b}{m_m} v_b$

Where $m_m$ is the mass of the man, $m_b$ is the mass of the book, and $v_m$ and $v_b$ are their velocities. Plugging in the given values, we can compute the speed of the man (ignoring the negative sign, because we care about the magnitude, not the direction):

$v_m=\frac{2.40kg}{78.5kg}(11.3m/s)=0.345m/s$

In words, the resulting speed of the man is 0.345m/s.

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3 years ago

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Imagine disease kills 85% of the wolf population. How would this affect the other organisms?

DIA [1.3K]

Whatever hunts the wolfs will become famished and have a population decline while whatever the wolf hunts will have a population growth since there are less predators

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3 years ago

Consider a Hydrogen atom with the electron in the n 8 shell. What is the energy of this system? (The magnitude of the ground sta

Shtirlitz [24]

Answer:

The energy of an electron in the 8th shell is given by: -0.2125 eV

The number of subshells is: 8

The number of orbitals is: 64

The number of electrons that fit on this shell is: 128

Explanation:

First, we find the energy of the electrons in the 8th shell. In order to do this, we recall that the energy of an electron (in the Hydrogen atom) whose principal number is n is given by:

$E_{n}=-13.6\frac{1}{n^{2}}$

Substituting n=8, we find that the energy is given by:

$E_{8} = -13.6\frac{1}{8^{2}}=-0.2125$

In order to find the number of subshells we recall that, for a given principal quantum number n, the possible values of the quantum number l, which corresponds to the number of subshells are:

0, 1, 2, ... , n-1

Since n = 8 in our problem, the possible values of l are: 0, 1, 2, 3, 4, 5, 6, 7. Therefore, the number of subshells are 8.

Now we continue with the number of orbitals. For every subshell l, we have 2l+1 possible values of m, which correspond to the orbitals. Since the possible values of l are: 0,1,2,3,4,5,6,7, therefore, we have to perform the sum:

$\sum_{l=0}^{7}(2l+1) = 8^2=64$