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2 years ago

‘The Universe is expanding.’ Justify this statement with the Big bang model of universe and Hubble’s Law.

Physics

1 answer:

Taya2010 [7]2 years ago

7 0

Explanation:

The expansion of the universe is the increase in distance between any two given ... Metric expansion is a key feature of Big Bang cosmology, is modeled mathematically with the ...

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A sound wave has a frequency of 500 Hz and a wavelength of 1.8 m. What is the wave speed of the sound wave? Question 1 options:

antoniya [11.8K]

Answer:

The wave speed of the sound wave is 900 $\frac{m}{s}$ .

Explanation:

Wavelength is the minimum distance between two successive points on the wave that are in the same state of vibration. It is expressed in units of length (m).

Frequency is the number of vibrations that occur in a unit of time. Its unit is s⁻¹ or hertz (Hz).

The propagation velocity is the speed with which the wave propagates in the medium, that is, it is the magnitude that measures the speed at which the wave disturbance propagates along its displacement. Relate the wavelength (λ) and the frequency (f) inversely proportional using the following equation: v = f * λ.

In this case:

f= 500 Hz
λ= 1.8 m

Replacing:

v= 500 Hz* 1.8 m

v= 900 $\frac{m}{s}$

<u><em>The wave speed of the sound wave is 900 </em></u> $\frac{m}{s}$ <u><em>.</em></u>

7 0

3 years ago

An electric charge, A, is placed carefully between two other charges, B and C, and experiences no net electric force. Do B

Brrunno [24]

Answer:

I do not have enough information to tell

Explanation:

This is deduced due to the fact that if the net force due to B and C on A is zero, the charges on B and C could either be positive or negative depending on the charge on A.

5 0

3 years ago

A 50.-kilogram rock rolls off the edge of a cliff. if it is traveling at a speed of 24.2 m/s when it hits the ground, what is th

ElenaW [278]

The correct answer to the question is : 29.88 m.

EXPLANATION :

As per the question, the mass of the rock m = 50 Kg.

The rock is rolling off the edges of the cliff.

The final velocity of the rock when it hits the ground v = 24 .2 m/s.

Let the height of the cliff is h.

The potential energy gained by the rock at the top of the cliff = mgh.

Here, g is known as acceleration due to gravity, and g = $9.8\ m/s^2$

When the rock rolls off the edge of the cliff, the potential energy is converted into kinetic energy.

When the rock hits the ground, whole of its potential energy is converted into its kinetic energy.

The kinetic energy of the rock when it touches the ground is given as -

Kinetic energy K.E = $\frac{1}{2}mv^2$ .

From above we know that -

Kinetic energy at the bottom of the cliff = potential energy at a height h

$\frac{1}{2}mv^2=\ mgh$

⇒ $v^2=\ 2gh$

⇒ $h=\ \frac{v^2}{2g}$

⇒ $h=\ \frac{(24.2)^2}{2\times 9.8}$

⇒ $h=\ 29.88\ m$

Hence, the height of the cliff is 29.88 m

5 0

3 years ago

HELP ME please

allochka39001 [22]

Answer:

Ruko zara kuch Time dedo na please

3 0

2 years ago

7. CALCULATE: How much work is done in each of

kifflom [539]

<h3>Answer</h3>

a. 8J

b. 90J

<h3>Notes formula</h3>

W = F × s

W = Work done (J)

F = Force (N)

s = distance (m)

<h3>Known that </h3>

a. F = 4N

s = 2m

b. F = 30N

s = 3m

<h3>Question</h3>

a. W = ..?

b. W = ..?

a. W = F × s

= 4N × 2m = 8J

b. W = F × s

= 30N × 3m = 90J

<em>#Moderators please don't be mean, dont delete my answers just to get approval from your senior or just to get the biggest moderation daily rank.</em>

6 0

2 years ago