What is the si unit of force

Which is the most accurate description of the plasma state of matter? A. It has a fixed volume. B. Its shape is not fixed. C. It

anastassius [24]

Answer:

Its shape is not fixed

Explanation:

Plasma is sometimes a subset of gases, whereas it is also a state of matter.

These two states are different.

No fixed shape for plasmas, no fixed volume.

Compared to solids and liquids plasmas are less dense.

Atoms are used in the making of Plasma.

In plasma state ions are the positively charged nuclei

When they gain or lose electrons these atoms and molecules acquire a positive or negative electrical charge, process is called ionization.

8 0

3 years ago

Our understanding of the H atom will help us learn about atoms with more electrons. The n =1 electron energy level of a H atom h

Mkey [24]

Answer:

a) What is the energy of the n = 5 level?

$E_{5} = - 8.70x10^{-20}J$

(b) Calculate the wavelength and frequency of a photon emitted when an electron jumps down from n = 5 to n = 1 in a H atom.

$\lambda = 94.9nm$ , $f = 3.16x10^{15}Hz$

Explanation:

The permitted energy for the atom of hydrogen according with the Bohr's model is defined as:

$E_{n} = -\frac{13.606 eV}{n^{2}}$ (1)

Or it can be expressed in Joules, since $1eV = 1.60x10^{-19}J$

$E_{n} = -\frac{2.18x10^{-18} J}{n^{2}}$

Where the value $-2.18x10^{-18}$ represents the energy of the ground state¹ and n is the principal quantum number.

<em>a) What is the energy of the n = 5 level? </em>

For the case of $n = 5$ :

$E_{5} = -\frac{2.18x10^{-18} J}{(5)^{2}}$

$E_{5} = -8.70x10^{-20}J$

So the energy of the $n = 5$ level is $-8.70x10^{-20}J$ .

<em>(b) Calculate the wavelength and frequency of a photon emitted when an electron jumps down from n = 5 to n = 1 in a H atom.</em>

The wavelength can be determined by means of the Rydberg formula:

$\frac{1}{\lambda} = R(\frac{1}{n_{f}^{2}}-\frac{1}{n_{i}^{2}})$ (2)

Where R is the Rydberg constant, with a value of $1.097x10^{7}m^{-1}$

For this particular case $n_{f} = 1$ and $n_{i} = 5$ :

$\frac{1}{\lambda} = 1.097x10^{7}m^{-1}(\frac{1}{(1)^{2}}-\frac{1}{(5)^{2}})$

$\frac{1}{\lambda} = 1.097x10^{7}m^{-1}(0.96)$

$\frac{1}{\lambda} = 10531200m^{-1}$

$\lambda = \frac{1}{10531200m^{-1}}$

$\lambda = 9.49x10^{-8}m$

Where $1m = 1x10^{9}nm$

$\lambda = 9.49x10^{-8}m$ . $\frac{1x10^{9}nm}{1m}$

$\lambda = 94.9nm$

The frequency can be found by means of:

$c = f\lambda$ (3)

Equation (3) can be rewritten in terms of $f$ :

$f = \frac{c}{\lambda}$

$f = \frac{3.00x10^{8}m/s}{9.49x10^{-8}m}$

$f = 3.16x10^{15}s^{-1}$

Where $1Hz = s^{-1}$

$f = 3.16x10^{15}Hz$

Key terms:

¹Ground state: State of minimum energy.

4 0

3 years ago

An object accelerates 2.0 m/s2 when a force of 12.0 newtons is applied to it. What is the mass of the object?

julia-pushkina [17]

Answer: 6kg

Explanation:

4 0

3 years ago

A man drops a rock into a well. (a) the man hears the sound of the splash 2.40 s after he releases the rock from rest. the speed

Burka [1]

Part (a)
Let h = depth of water surface from the top of the well, m

Because the stone is dropped, its initial velocity is zero.
Let t₁ = time for the stone to drop, s
Then
h = (1/2)*(9.8 m/s²)*(t₁ s)²
t₁ = √(h/4.9) s = 0.4518√h s

The velocity of sound is 336 m/s.
The time for the sound wave to travel from the water surface to the top of the well is
t₂ = h/336 m/s

Because the time before the sound is heard is 2.4 s, therefore
t₁ + t₂ = 2.4
0.45181√h + h/336 = 2.4
Multiply through by 336.
151.8082√h + h = 806.4
h - 806.4 = -151.8082√h
h² - 1612.8h + 6.5028 x 10⁵ = 2.3046 x 10⁴h
h² - 2.4659 x 10⁴h + 6.5028 x 10⁵ = 0

Solve with the quadratic formula.
h = 0.5[2.4659 x 10⁴ +/- 2.4606 x 10⁴]
= 24632 m or 26.5 m

Test the two answers.
When h = 24632,
t₁ = 0.4518√(24632) = 70.9 s (Not acceptable)
When h = 26.5 m,
t₁ = 0.4518√(26.5) = 2.3258 s, t₂ = 26.5/336 = 0.0789 s,
t₁+t₂ = 2.4 s (CORRECT)

Answer: h = 26.5 m

Part (b)
If travel time for the sound is ignored, then
0.4518√h = 2.4
h = (2.4/0.45118)² = 28.2 m
The percent error is 100*[(28.2 - 26.5)/26.5] = 6.42%

Answer: The error is 6.4%

4 0

3 years ago

Sterling Archer, despite failing repeatedly at pole-vaulting, is determined to master the skill. He is holding a vaulting pole p

LekaFEV [45]

Answer:

left hand: 133 N upward

right hand: 83N downward

Explanation:

10 cm = 0.1m

Let g = 10m/s2. The pole gravity force would be $F_p = 5*10 = 50 N$ . Suppose the pole mass distribution is uniform, this means the center of mass is at its geometric center, aka 5/2 = 2.5m from the top end.

In order for the system to stay balanced, the total net force and net moment must be 0

$F_L + F_R = F_p = 50 N$ where $F_L, F_R$ are the forces exerted by his left and right hand, respectively.

We will pick his right hand (0.1 m from the top end) as moment pivot point. The total moment generated by pole gravity and his left hand must be 0

Distance (or moment arm length) from pole center to his right hand is $R_p = 2.5 – 0.1 = 2.4 m$

Moment generated by gravity around his right hand is: $M_p = F_pR_p = 50*2.4 = 120 Nm$ counter-clockwise

Distance (or moment arm length) from left hand to his right hand is $R_L = 1 – 0.1 = 0.9 m$

Moment generated by force from his left hand around his right hand is: $M_L = F_LR_L = 1.9F_L Nm$ clockwise

Since the total moment must be 0, the clockwised-direction moment = counterclockwised-direction moment:

$0.9F_L = 120$

$F_L = 120 / 0.9 = 133 N$ upward

Therefore, the force exerted by his right hand must be 50 – 133 = -83 N or 83N downward

3 0

3 years ago

What is the si unit of force ​

What is the si unit of force