a train traveling at 72 km/h crosses a platform in 30 seconds what is the length of the platform in meters

A boy travels 12km east wards to a point B and then 5km southwards to another point C. Calculate the difference between the magn

shepuryov [24]

The difference b/w the displacement and total distance traveled is 4km.

Explanation.

▪ total distance - displacement

= 17 km - 13 km

= 4 km...answer

7 0

2 years ago

In a longitudinal wave, amplitude can be measured

nignag [31]

Answer:

Compressions

Explanation:

A longitudinal wave is a wave in which the direction of propagation of the wave and the direction of the displacement of the particles of the wave are parallel.

As the wave propagates, the particles do not move, but, oscillate back and forth about their equilibrium position, and there are thus regions of high pressure called compressions and regions of low pressure called rarefactions.

The amplitude is thus the distance between successive compressions.

4 0

2 years ago

You are working in a biology lab and learning to use a new ultracentrifuge for blood tests. The specifications for the centrifug

Sloan [31]

Answer:

Yes, correct

Explanation:

velocity, v = 470 m/s

radius, r = 0.15 m

The radial acceleration is the centripetal acceleration which always acts towards the centre of the circular centrifuge.

The formula for the centripetal acceleration is given by

$a =\frac{v^{2}}{r}$

$a =\frac{470^{2}}{0.15}$

a = 1472666.667

a = 150272.1 g

According to the question, we can get the acceleration as mentioned. So the claim is correct.

7 0

3 years ago

Read 2 more answers

Obliquity describes:

Pachacha [2.7K]

Answer:

c. the tilt of the axis of rotation with respect to the Plane of the Ecliptic

Explanation:

The inclination of the ecliptic (or known only as obliqueness) refers to the angle of the axis of rotation with respect to a perpendicular to the plane of the eclipse. He is responsible for the seasons of the year that the planet Earth lends. It is not constant but changes through the movement of nutation. The terrestrial plane of Ecuador and the ecliptic intersect in a line that has an end at the point of Aries and at the diametrically opposite point of Libra.

When the Sun crosses the Aries, the spring equation occurs (between March 20 and 21, the beginning of spring in the northern hemisphere and the early autumn of the southern hemisphere), and from which the Sun is in the North Hemisphere; Pound until you reach the point of the autumn equinox (around September 22-23, beginning fall in the northern hemisphere and spring in the southern hemisphere).

4 0

3 years ago

Ejection of Electrons from Hydrogen by Incident Photons Light of wavelength 80 nm is incident on a sample of hydrogen gas, resul

timofeeve [1]

Answer:

a) $K_{max}$ = 1.9 eV = 3.04 10⁻¹⁹ J,b ) This means that some electrons are at the first excited level of the hydrogen atom, which is highly likely as the temperature rises.

Explanation:

a) To calculate the maximum kinetic energy of the expelled electrons let's use the relationships of the photoelectric effect

$K_{max}$ = h f - Φ

Where K is the kinetic energy, h the Planck constant that is worth 6.63 10⁻³⁴ Js, f the frequency and Φ the work function

The speed of light is related to wavelength and frequency

c = λ f

Let's analyze the work function, it is the energy needed to start an electron from a metal, in this case to start an electron from a hydrogen atom its fundamental energy is needed, so

Φ= E₀ = 13.6 eV

let's replace and calculate the energy of the incident photon

E = h c / λ

E = 6.63 10⁻³⁴ 3 10⁸/80 10⁻⁹

E = 2,486 10⁻¹⁸ J

Let's reduce to eV

E = 2,486 10⁻¹⁸ (1 eV / 1.6 10⁻¹⁹)

E = 15.5 eV

Now we can calculate the kinetic energy

$K_{max}$ = h c / f - fi

$K_{max}$ = 15.5 -13.6

$K_{max}$ = 1.9 eV

b) Extra energy = 10.2 eV

The total kinetic energy of electrons is

Total kinetic energy = 1.9 +10.2 = 12.1 eV

For the calculation we are assuming that all the electors are in the hydrogen base state, but for temperatures greater than 0K some electors may be in some excited state, so less energy is needed to tear them out of hydrogen atom.

Let's analyze this possibility

ΔE = E photon - Total kinetic energy electron

ΔE = 15.5 - 12.1

ΔE = 3.4 eV

If we use the Bohr ratio for the hydrogen atom

$E_{n}$ = 13.606 / n2

n = √ 13.606 / En

n = √ (13606 / 3.4)

n = 2

This means that some electrons are at the first excited level of the hydrogen atom, which is highly likely as the temperature rises.

8 0

3 years ago