A l'aide du document 1, écrire une synthèse sur la composition de l'atome en utilisant les mots

(d)

deff fn [24]

Answer:

Frequency = 24 × 10⁸ Hz

Explanation:

Given the following data;

Speed = 3 × 10⁸ m/s

Wavelength = 0.125 meters

To find the frequency of the electromagnetic wave;

Mathematically, the speed of a wave is given by the formula;

Speed = Wavelength × frequency

Substituting into the formula, we have;

3 × 10⁸ = 0.125 × frequency

Frequency = (3 × 10⁸)/0.125

Frequency = 24 × 10⁸ Hz

3 0

3 years ago

Physics question 28 plz help me

Alexus [3.1K]

Answer:

a. I = 30 A

b. E = 1080000 J = 1080 KJ

c. ΔT = 12.86°C

d. Cost = $ 4.32

Explanation:

a.

The current in the coil is given by Ohm's Law:

$V = IR\\I = \frac{V}{R}$

where,

I = current = ?

V = Voltage = 120 V

R = Resistance = 4 Ω

Therefore,

$I = \frac{120\ V}{4 \Omega}\\$

I = 30 A

b.

The energy can be calculated as:

$E = VIt\\E = (120\ V)(30\ A)(5\ min)(\frac{60\ s}{1\ min})\\$

E = 1080000 J = 1080 KJ

c.

For the increase in the temperature of water:

$E = mC\Delta T\\$

where,

m = mass of water = 20 kg

C = specific heat of water = 4.2 KJ/kg.°C

Therefore,

$1080\ KJ = (20\ kg)(4.2\ KJ/kg.^oC)\Delta T$

ΔT = 12.86°C

d.

First, we will calculate the total energy consumed:

$E=(Power)(Time)\\E=VI(Time)\\E = (120\ V)(30\ A)(0.5\ h/d)(30\ d)\\E = 54000\ Wh\\E = 54 KWh$

Now, for the cost:

$Cost = (Unit\ Cost)(Energy)\\Cost = (\$ 0.08\KWh)(54\ KWh)$

Cost = $ 4.32

7 0

3 years ago

In an experiment, the explanation of the expected outcome, based on research, is the _______________.

vladimir1956 [14]

C. Hypothesis
The hypothesis is presented as an explanation of the observed results.

7 0

3 years ago

vA 61.2-kg circus performer is fired from a cannon that is elevated at an angle of 57.8 ° above the horizontal. The cannon uses

dsp73

Answer:

The effective spring constant of the firing mechanism is 1808N/m.

Explanation:

First, we can use kinematics to obtain the initial velocity of the performer. Since we know the angle at which he was launched, the horizontal distance and the time in which it's traveled, we can calculate the speed by:

$v_0_x=\frac{x}{t}\\ \\v_0\cos\theta=\frac{x}{t}\\\\v_0=\frac{x}{t\cos\theta}$

(This is correct because the horizontal motion has acceleration zero). Then:

$v_0=\frac{20.8m}{(2.60s)\cos57.8\°}\\\\v_0=15.0m/s$

Now, we can use energy to obtain the spring constant of the firing mechanism. By the conservation of mechanical energy, considering the instant in which the elastic band is at its maximum stretch as t=0, and the instant in which the performer flies free of the bands as final time, we have:

$E_0=E_f\\\\U_e=K\\\\\frac{1}{2}kx^2=\frac{1}{2}mv^2\\\\\implies k=\frac{mv^2}{x^2}$