All categories

4 years ago

Is cold fusion science or pseudoscience

1 answer:

kondor19780726 [428]4 years ago

5 0

The experiments that claimed to demonstrate cold fusion were found
to have been faulty by others who reviewed them. Also, nobody else
was able to reproduce the finding in other laboratories. In the world
of Science, this pretty much says that the initial claims were unfounded.

You might be interested in

One day, after pulling down your window shade, you notice that sunlight is passing through a pinhole in the shade and making a s

DedPeter [7]

Complete Question

One day, after pulling down your window shade, you notice that sunlight is passing through a pinhole in the shade and making a small patch of light on the far wall. Having recently studied optics in your physics class, you're not too surprised to see that the patch of light seems to be a circular diffraction pattern. It appears that the central maximum is about 2 cm across, and you estimate that the distance from the window shade to the wall is about 5 m.

Required:

Estimate the diameter of the pinhole.

Answer:

The diameter is $d =0.000336 m$

Explanation:

From the question we are told that

The central maxima is $D= 2cm = \frac{2}{100} = 0.02m$

The distance from the window shade is $L = 5m$

The average wavelength of the sun is mathematically evaluated as

$\lambda_{ave } = \frac{\lambda_i + \lambda_f}{2}$

Generally the visible light spectrum has a wavelength range between 400 nm to 700 nm

So the initial wavelength of the sun is $\lambda _i = 400nm$

and the final wavelength is $\lambda_f = 700nm$

Substituting this into the above equation

$\lambda_{sun} = \frac{400nm +700nm}{2}$

$= 550nm$

The diameter is evaluated as

$d = \frac{2.44 \lambda_{sun} L}{D}$

substituting values

$d = \frac{2.44 * 550*10^{-9} * 5 }{0.02}$

$d =0.000336 m$

5 0

3 years ago

The current theory of the structure of the

Mariana [72]

Answers:

a) $2.82(10)^{21} kg$

b) $1410 J$

c) $36.62 m/s$

Explanation:

<h3>a) Mass of the continent</h3>

Density $\rho$ is defined as a relation between mass $m$ and volume $V$ :

$\rho=\frac{m}{V}$ (1)

Where:

$\rho=2720 kg/m^{3}$ is the average density of the continent

$m$ is the mass of the continent

$V$ is the volume of the continent, which can be estimated is we assume it as a a slab of rock 5300 km on a side and 37 km deep:

$V=(length)(width)(depth)=(5300 km)(5300 km)(37 km)=1,030,330,000 km^{3} \frac{(1000 m)^{3}}{1 km^{3}}=1.03933(10)^{18} m^{3}$

Finding the mass:

$m=\rho V$ (2)

$m=(2720 kg/m^{3})(1.03933(10)^{18} m^{3})$ (3)

$m=2.82(10)^{21} kg$ (4) This is the mass of the continent

<h3>b) Kinetic energy of the continent</h3>

Kinetic energy $K$ is given by the following equation:

$K=\frac{1}{2}mv^{2}$ (5)

Where:

$m=2.82(10)^{21} kg$ is the mass of the continent

$v=4.8 \frac{cm}{year} \frac{1 m}{100 cm} \frac{1 year}{365 days} \frac{1 day}{24 hours} \frac{1 hour}{3600 s}=1(10)^{-9} m/s$ is the velocity of the continent

$K=\frac{1}{2}(2.82(10)^{21} kg)(1(10)^{-9} m/s)^{2}$ (6)

$K=1410 J$ (7) This is the kinetic energy of the continent

<h3>c) Speed of the jogger</h3>

If we have a jogger with mass $m=77 kg$ and the same kinetic energy as that of the continent $1413 J$ , we can find its velocity by isolating $v$ from (5):

$v=\sqrt{\frac{2 K}{m}}$ (6)

$v=\sqrt{\frac{2 (1413 J)}{77 kg}}$

Finally:

$v=36.62 m/s$ This is the speed of the jogger

5 0

4 years ago

What is the answers

andriy [413]

Salt is a substance because a substance is a material that has constant composition regardless of its source. Salt is the only option that matches this description

5 0

3 years ago

Samples of different materials, A and B, have the same mass, but the sample

Effectus [21]

Answer:

B. The particles that make up material B have more mass than the

particles that make up material A.

Explanation:

3 0

3 years ago

(15 POINTS) Victor drew a diagram to show the life cycle of a low-mass star.

Evgen [1.6K]

The answer is c so the area can grow

4 0

3 years ago

Read 2 more answers