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3 years ago

Which property describes an electromagnetic wave and not a mechanical wave?

2 answers:

7 0

The property that describes an electromagnetic wave and not a mechanical wave is travels in a a vacuum. That will make the correct answer B. I hope that helps you.

zhuklara [117]3 years ago

7 0

B. travels in a vacuum

Explanation:

Electromagnetic waves are periodic oscillations of an electric field and a magnetic field, which occur perpendicular to the direction of propagation of the wave. The main property of these waves is that they do not a medium to propagate: in fact, electromagnetic waves can also travel in a vacuum (e.g. they can travel in space).

On the contrary, mechanical waves are oscillations of the particles in a medium, so they do need a medium to propagate.

Therefore, the main difference between electromagnetic waves and mechanical waves is that the former can travel in a vacuum, while the latter cannot.

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Four particles are in a 2-d plane with masses, x- and y- positions, and x- and y- velocities as given in the table below: what i

Arte-miy333 [17]

I attached the picture of the missing table.
Center of mass is the point such that if you apply force to it, the system would move without rotating.
We can use following formula to calculate the center of mass:
$R=\frac{1}{M}\sum_{i=1}^{n=i}m_ir_i$
Where M is the sum of the masses of all particles.
Part 1
To calculate the x coordinate of the center of mass we will use this formula:
$R_x=\frac{1}{M}\sum_{i=1}^{n=i}m_ix_i$
I will do all the calculations in the google sheet that I will share with you.
For the x coordinate of the center of mass we get:
$R_x=0.96m$
Part 2
To calculate the y coordinate of the center of mass we will use this formula:
$R_y=\frac{1}{M}\sum_{i=1}^{n=i}m_iy_i$
I will do all the calculations in the google sheet that I will share with you.
For the x coordinate of the center of mass we get:
$R_y=-0.84m$
Part 3
We will calculate speed along x and y-axis separately and then will add them together.
$v_x=\frac{\sum_{i=1}^{n=i}m_iv_x_i}{M}$
$v_y=\frac{\sum_{i=1}^{n=i}m_iv_y_i}{M}$
Total velocity is:
$v=\sqrt{v_x^2+v_y^2}$
Once we calculate velocities we get:
$v_x=-1.08\frac{m}{s}\\ v_y=-0.03\frac{m}{s}\\ v=\sqrt{(-1.08)^2+(-0.03)^2}=1.08\frac{m}{s}$
Part 4
Because origin is left to our center of mass(please see the attached picture) placing fifth mass in the origin would move the center of mass to the left along the x-axis.
Part 5
If you place fifth mass in the center of the mass nothing would change. The center of mass would stay in the same place.
Here is the link to the spreadsheet:
https://docs.google.com/spreadsheets/d/1SkQHbI1BxiJnwpWbLmP0XWgcNPrGquH1K2MfN6cznVo/edit?usp=sharing

3 0

3 years ago

Determine the minimum applied force p required to move wedge a to the right. the spring is compressed a distance of 185 mm. negl

Pie

By equation of equilibrium and friction:

Fb = Kx = 15(0.175) = 2.625 kN.

The wedge is on the verge of moving right then slipping will have to occur at both contact surfaces.

Fa = usNa = 0.35Na

Fb = 0.35Nb

Nb = 2.625 = 0; Nb = 2.625 kN

Nacos10 – 0.35Na sin 10 = 2.625 = 0

Na = 2.841 kN

P – (0.35 * 2.625) – 0.35 (2.841) cos 10 – 2.841 sin 10 = 0

P = 2.39 kN

7 0

4 years ago

Explain why it is not possible to determine the type of an atom by simply knowing how many neutrons it has.

nikklg [1K]

Answer:

Explanation:

There are isotopes, which are the same atom, but different number of neutrons, so only neutrons cannot determine the atom

6 0

3 years ago

How did the electron change the model of the atom?

Evgesh-ka [11]

According to John Dalton, atoms are indivisible which means that they can not be broken down into smaller particles. However, J.J Thomson have proven the existence of electrons. The existence of sub-atomic particles disproved Dalton's theory. Thomson conducted his experiment using a cathode ray-tube.

4 0

3 years ago

Two cats are sitting on a 30 m hill. One cat

V125BC [204]

Answer:

Cat with 6 kg sitting on a 30 meter hill has greater potential energy.

Explanation:

gravitational potential energy (J) = mass (kg) × gravitational field × height (m)

gravitational field in Earth is 10 N/kg = <u>fixed unit</u>

<h3 /><h3><u>Given</u>:</h3>

1st Cat: 4 kg

2nd Cat: 6 kg

Both of their height is 30 meters.

<h3><u>Solve for g.p.e</u>:</h3>

1st cat = mgh = 4 × 10 × 30 = 1200 Joules

2nd cat = mgh = 6 × 10 × 30 = 1800 Joules

3 0

2 years ago